Aav vector for treatment of friedreich&#39;s ataxia

ABSTRACT

Provided herein are nucleic acids, recombinant adeno-associated viral particles, compositions and methods related to treating Friedreich&#39;s ataxia. In some examples, the nucleic acids, recombinant adeno-associated viral particles, compositions and methods involve us of a FXN coding sequence, a truncated FXN 3′ UTR, and a prompter.

RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 62/152,780, entitled “AAV VECTOR FORTREATMENT OF FRIEDREICH'S ATAXIA” filed on Apr. 24, 2015, which isherein incorporated by reference in its entirety.

BACKGROUND

Friedreich's ataxia is a genetic disease that causes damage to thenervous system, resulting in degeneration of the spinal cord andperipheral nerves. Friedreich's ataxia is caused by a mutation in theFXN gene that results in an expansion of an intronic GAA repeat, whichleads to reduced expression of the mitochondrial protein frataxin. Thereis currently no approved cure for Friedreich's ataxia.

SUMMARY

Aspects of the disclosure relate to nucleic acids, recombinantadeno-associated virus (rAAV) particles, compositions, and methodsrelated to gene therapy for Friedreich's ataxia (FRDA).

As described herein, a rAAV nucleic acid vector was designed containinga codon-optimized human FXN gene with a truncated human FXN 3′ UTR,operably linked to a promoter. When this vector was delivered in a rAAVparticle to cardiomyocytes differentiated from induced pluripotent stemcells (IPSC) derived from FRDA, the cells had increased mitochondrialactivity. This improvement in mitochondrial activity was correlated withincreased levels of FXN expression in vitro. It is believed that thisvector may be useful for treatment of FRDA.

In some aspects, the disclosure provides a nucleic acid comprising anexpression construct comprising a human frataxin (FXN) coding sequenceand a truncated human FXN 3′ untranslated region (UTR) operably linkedto a promoter (e.g., a Desmin promoter, a CBA promoter, a hFXNPro, orother suitable promoter), wherein the expression construct is flanked oneach side by an inverted terminal repeat sequence (e.g., an AAV ITR).

In some embodiments, the human FXN coding sequence is codon-optimizedfor expression in human cells. In some embodiments, the FXN codingsequence comprises the sequence of SEQ ID NO: 1. In some embodiments,the promoter comprises one or more of the following: a Desmin promoter,a chicken 3-actin (CBA) promoter, or an endogenous human FXN promoter(hFXNPro), or a fragment or derivative of one or more thereof sufficientto drive expression of the FXN coding sequence (e.g., in human cells).In some embodiments, the Desmin promoter comprises the sequence of SEQID NO: 2. In some embodiments, the CBA promoter comprises the sequenceof SEQ ID NO: 7. In some embodiments, the hFXNPro comprises the sequenceof SEQ ID NO: 8. In some embodiments, the truncated human FXN 3′ UTR hasthe sequence of SEQ ID NO: 3. In some embodiments, the expressionconstruct comprises the sequence of SEQ ID NO: 4 (or a portion thereofcomprising a gene of interest under the control of a promoter ofinterest, optionally flanked by ITR sequences). In some embodiments, thenucleic acid is a recombinant adcno-associated virus (rAAV) vector. Insome embodiments, the nucleic acid is a single-stranded orself-complementary rAAV nucleic acid vector.

Other aspects of the disclosure relate to a recombinant adeno-associatedvirus (rAAV) particle comprising a nucleic acid as described herein. Insome embodiments, the nucleic acid comprises an expression constructcomprising a human frataxin (FXN) coding sequence and a truncated humanFXN 3′ untranslated region (UTR) operably linked to a promoter (e.g., aDesmin promoter, a CBA promoter, a hFXNPro, or other suitable promoter),wherein the expression construct is flanked on each side by an invertedterminal repeat sequence.

In some embodiments, the human FXN coding sequence is codon-optimizedfor expression in human cells. In some embodiments, the FXN codingsequence comprises the sequence of SEQ ID NO: 1. In some embodiments,the promoter comprises one or more of the following: a Desmin promoter,a chicken β-actin (CBA) promoter, or an endogenous human FXN promoter(hFXNPro), or a fragment or derivative of one or more thereof sufficientto drive expression of the FXN coding sequence (e.g., in human cells).In some embodiments, the Desmin promoter comprises the sequence of SEQID NO: 2. In some embodiments, the CBA promoter comprises the sequenceof SEQ ID NO: 7. In some embodiments, the hFXNPro comprises the sequenceof SEQ ID NO: 8. In some embodiments, the truncated human FXN 3′ UTR hasthe sequence of SEQ ID NO: 3. In some embodiments, the expressionconstruct comprises the sequence of SEQ ID NO: 4 (or a portion thereofcomprising a gene of interest under the control of a promoter ofinterest, optionally flanked by ITR sequences). In some embodiments, thenucleic acid is a recombinant adeno-associated virus (rAAV) vector. Insome embodiments, the nucleic acid is a single-stranded orself-complementary rAAV nucleic acid vector.

In some embodiments, the rAAV particle is an AAV9 particle.

In yet other aspects, the disclosure relates to a composition comprisinga plurality of an rAAV particle as described herein. In someembodiments, the rAAV panicle comprises a nucleic acid as describedherein.

In some embodiments, the human FXN coding sequence is codon-optimizedfor expression in human cells. In some embodiments, the FXN codingsequence comprises the sequence of SEQ ID NO: 1. In some embodiments,the promoter comprises one or more of the following: a Desmin promoter,a chicken β-actin (CBA) promoter, or an endogenous human FXN promoter(hFXNPro), or a fragment or derivative of one or more thereof sufficientto drive expression of the FXN coding sequence (e.g., in human cells).In some embodiments, the Desmin promoter comprises the sequence of SEQID NO: 2. In some embodiments, the CBA promoter comprises the sequenceof SEQ ID NO: 7. In some embodiments, the hFXNPro comprises the sequenceof SEQ ID NO: 8. In some embodiments, the truncated human FXN 3′ UTR hasthe sequence of SEQ ID NO: 3. In some embodiments, the expressionconstruct comprises the sequence of SEQ ID NO: 4 (or a portion thereofcomprising a gene of interest under the control of a promoter ofinterest, optionally flanked by ITR sequences). In some embodiments, thenucleic acid is a recombinant adeno-associated virus (rAAV) vector. Insome embodiments, the nucleic acid is a single-stranded orself-complementary rAAV nucleic acid vector.

In some embodiments, the rAAV particle is an AAV9 particle (e.g., therAAV particle comprises viral capsid proteins of serotype 9).

In some embodiments, the composition further comprises apharmaceutically acceptable carrier.

In other aspects, the disclosure provides a method of treatingFriedreich's ataxia, the method comprising administering atherapeutically effective amount of an rAAV particle as described aboveor as described elsewhere herein or a composition as described above oras described elsewhere herein to a subject having Friedrcich's ataxia.In some embodiments, the rAAV particle or composition are administeredvia intravenous injection. In some embodiments, the rAAV particle orcomposition are administered via intrathecal injection. In someembodiments, the rAAV particle or composition are administered viaintracisternal injection. In some embodiments, the rAAV particle orcomposition are administered via intravenous injection and intrathecalinjection. In some embodiments, the rAAV particle or composition areadministered via intravenous injection and intracisternal injection.

In some embodiments, the ratio of rAAV particle administered to thesubject via intravenous injection to rAAV particle administered to thesubject via intrathecal injection is between 10:1 and 1:1 (e.g., around5:1, or around 10:1). In some embodiments, the ratio of rAAV particleadministered to the subject via intravenous injection to rAAV particleadministered to the subject via intrathecal injection is between 1:1 and1:10 (e.g., around 1:5, or around 1:10). In some embodiments, the ratioof rAAV particle administered to the subject via intravenous injectionto rAAV particle administered to the subject via intracisternalinjection is between 10:1 and 1:1 (e.g., around 5:1, or around 10:1). Insome embodiments, the ratio of rAAV particle administered to the subjectvia intravenous injection to rAAV particle administered to the subjectvia intracisternal injection is between 1:1 and 1:10 (e.g., around 1:5,or around 1:10).

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentdisclosure, which can be better understood by reference to one or moreof these drawings in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1 is a non-limiting plasmid map showing an expression constructcontaining a Desmin (DES) promoter, a codon-optimized human FXN codingsequence, and a truncated human FXN 3′ UTR, the expression constructflanked by inverted terminal repeat sequences (ITRs).

FIG. 2A shows an exemplary photograph of renal epithelial cells (REC)isolated from FRDA patients.

FIG. 2B shows an exemplary photograph of induced pluripotent stem cells(IPSCs) generated from the RECs.

FIG. 2C shows a photograph of a contracting cardiomyocyte generated fromthe IPSCs.

FIG. 3A shows a series of exemplary photographs of cardiomyocytesgenerated from the IPSCs stained with different markers. (i) shows DAPIstaining, (ii) shows NKX2.5 staining, (iii) shows TroponinT staining,and (iv) shows an overlay of (i)-(iii).

FIG. 3B shows a series of exemplary photographs of neural progenitorcells (NPCs) generated from the IPSCs stained with different markers.(v) and (vi) show staining with Neurofluor CDr3 and Hoechst dye 33258.(vii) and (viii) show phase images of NPC cell morphology.

FIG. 4 shows an image of an exemplary Western blot stained with ananti-frataxin antibody. “+” is FA2 cells transiently transfected withthe FXN expression plasmid. “−” is FA2 cells that are not transfected, 1ug, 5 ug, and 10 ug are amounts of purified FXN.

FIG. 5A shows exemplary aconitase activity in FRDA patient-derivedcells. FA2=untreated FRDA cells, FA2+FXN=FRDA cells transientlytransfected with the FXN expression plasmid, CTRL=Healthy control cells.CTRL+FXN=healthy control cells transiently transfected with the FXNexpression plasmid.

FIG. 5B shows exemplary aconitase activity in FRDA patient-derivedcells. FA2 CTRL=FRDA cell without transfection. FA2 TX 1 μg=FRDA cellstransfected with 1 μg of plasmid, FA2 TX 5 μg=FRDA cells transfectedwith 5 μg of plasmid, FA2 TX 10 μg=FRDA cells transfected with 10 μg ofplasmid.

FIG. 6 shows an exemplary map of a Desmin promoter.

DETAILED DESCRIPTION

Friedrich's ataxia (FRDA) is an autosomal recessive disorder caused by atrinucleotide repeat expansion (TNR) of the frataxin (FXN) gene, onchromosome 9q 12-13, which leads to a deficiency in the mitochondrialprotein frataxin (FXN). FRDA affects 1 in 50,000 people worldwide and ischaracterized by progressive neural degeneration, such as ataxia,sensory loss, muscle weakness, and hypertrophic cardiomyopathy. Symptomsgenerally present at puberty and patients have a shorter than normallife expectancy reaching 40-50 years of age.

Frataxin is a highly conserved, 210 amino acid (˜17 kDa) protein encodedin the nucleus. While frataxin's specific function remains unclear,homozygous deletions are embryonically lethal. Evidence suggestsfrataxin is involved in iron metabolism, iron storage, iron-sulfurcluster (ISC) formation, and protection against reactive oxygen species(ROS). Dysregulation of FXN leads to iron accumulation in themitochondria and insufficient iron in the cytoplasm. Excessmitochondrial iron increases the incidence of iron-catalyzed reductionof hydrogen peroxide generating toxic ROS. The increase in ROS disruptsiron homeostasis in the mitochondria and affects the ISC aconitase, amajor component of cellular respiration.

Currently patients with FRDA receive palliative care as there is no FDAapproved treatment.

The major neurological symptoms of FRDA include muscle weakness andataxia, a loss of balance and coordination. FRDA mostly affects thespinal cord and the peripheral nerves that connect the spinal cord tothe body's muscles and sensory organs. FRDA affects the function of thecerebellum and also the musculature of the heart. There is a highprevalence of diabetes in FRDA patients as well. FXN deficiency inpancreatic islet cells causes diabetes (Ristow. M, el al., J ClinInvest. 112(4): 527-534, 2003).

In some embodiments, the neurological degeneration in FRDA patientsneeds to be addressed. In some embodiments, the cardiac disease in FRDApatients needs to be addressed. In some embodiments, there is a need forstrategies to treat the systemic manifestations of the disease, whichmay include disease in the heart, CNS and/or pancreatic islet cells.

Over the past decade the field of gene therapy for the treatment ofgenetic diseases has made a resurgence including marketing authorizationfor an AAV product in the EU. In some embodiments, the fundamentalprinciple is based on the ability to restore proper gene function intarget tissues.

Herein are disclosed nucleic acids, compositions and methods that can beused to achieve global gene transfer using AAV vectors, and that cantarget both the neurological and cardiac impairment in FRDA. Herein,“global” refers to an entire organ, system of the body (e.g., CNS) orbodxiy. The disclosed nucleic acids encoding FXN, compositions andmethods, which relate to both choice of promoter and routes of rAAVparticle delivery to a subject, enable targeting multiple affectedorgans in a subject with FRDA, including cardiac muscle, pancreas (e.g.,pancreatic islet cells), and/or CNS (e.g., dorsal root ganglia, and thecerebellum).

According to the disclosure, a gene therapy strategy that increasesfrataxin levels may be useful to treat FRDA or one or more symptomsthereof.

Adeno-associated viruses (AAVs) are among the most common vectors usedin gene therapy due to persistent, robust gene expression, a lack oftoxicity, and limited immune response. However, challenges inAAV-mediated neural delivery and targeting have yet to be fullycharacterized.

As described herein, a rAAV-FXN vector driven by a promoter sequence(e.g., a Desmin promoter) was developed and shown to be capable ofincreasing expression of frataxin and restoring mitochondrial functionin cells from FRDA patients.

Recombinant Adeno-Associated Virus (rAAV) Particles and Nucleic Acids

Aspects of the disclosure relate to recombinant AAV (rAAV) particles andnucleic acids. In some embodiments, a nucleic acid is provided, thenucleic acid comprising an expression construct containing a FXN codingsequence (e.g., a human FXN coding sequence) linked to a promoter (e.g.,a Desmin promoter, for example a human Desmin promoter, a CBA promoter,a hFXNPro, or other suitable promoter). In some embodiments, theexpression construct further contains a FXN 3′ untranslated region (UTR)that is 3′ to the FXN coding sequence. In some embodiments, theexpression construct is flanked on each side by an inverted terminalrepeat sequence (e.g., an AAV ITR).

Recombinant AAV (rAAV) nucleic acids are, herein, equivalent to rAAVnucleic acid vectors (e.g., a plasmid that is used to prepare a rAAV, anucleic acid comprising a gene of interest and a promoter flanked byITRs that are packaged in an rAAV particle, or other nucleic aciddescribed herein that comprises or encodes a nucleic acid that ispackaged in a rAAV, or that encodes one or more viral proteins).Accordingly, rAAV nucleic acids can be circular, linear,single-stranded, or double-stranded, depending on the context. In someembodiments, a nucleic acid is an RNA molecule. In some embodiments, anucleic acid is a DNA molecule. In some embodiments, recombinant AAV(rAAV) vectors can be nucleic acid vectors that are used to transfectcells in which the expression construct that is comprised by the vectoris packaged (or encapsidated) into rAAV particles. In some embodiments,rAAV vectors can be the nucleic acid flanked by rrRs (and including theITRs) that is packaged in a rAAV.

It should be appreciated that a composition or nucleic acid describedherein with reference to a particular sequence (e.g., with reference toa particular SEQ ID NO:) can be provided as a composition or nucleicacid (e.g., RNA or DNA) comprising a single-stranded nucleic acid havingthat sequence, or a composition or nucleic acid (e.g., RNA or DNA)comprising a single-stranded nucleic acid having the complement of thatsequence, or a composition or nucleic acid (e.g., RNA or DNA) comprisinga double-stranded nucleic acid one strand of which has that sequence, ora composition or nucleic acid (e.g., RNA or DNA) comprising a portion ofone or more of such nucleic acids, or a combination thereof.

In some embodiments, the FXN coding sequence encodes a human frataxinprotein. An exemplary human frataxin protein is shown below:

Exemplary human FXN protein (SEQ ID NO: 6)MWTLGRRAVAGLLASPSPAQAQTLTRVPRPAELAPLCGRRGLRTDIDATCTPRRASSNQRGLNQIWNVKKQSVYLMNLRKSGTLGHPGSLDETTYERLAEETLDSLAEFFEDLADKPYTFEDYDVSFGSGVLTVKLGGDLGTYVINKQTPNKQIWLSSPSSGPKRYDWTGKNWVFSHDGVSLHELLAAELTKALKTKLDLSWLAYSGKDAIDIPSPVLRTLKAIRPRPQLHYAAEVCFLLLLLFTFFTPAFEDSWAMCHSSVERMCCLLPCPQVLIFNFYGRFFGLSDFLPHMIPLIFYNVLCLYLNITTFKKAK

In some embodiments, the FXN coding sequence is codon-optimized forexpression in human cells, e.g., by adjusting codon usage within thecoding sequence to codons commonly used by human cells. In someembodiments, the FXN coding sequence is further optimized to removeextra GC content, ribosomal binding sites, consensus and cryptic splicesites, repeats, and/or secondary structures. Optimization of codingsequences (e.g., codon-optimization) can be accomplished using anymethod known in the art. e.g., using GeneOptimizer® software fromLifeTechnologies. In some embodiments, the codon-optimized human FXNcoding sequence is at least 80%, 85%, 90%, 95%, 96%, 97%9, 98%, 99%,100% identical to the sequence of SEQ ID NO: 1. In some embodiments, thecodon-optimized human FXN coding sequence comprises the sequence of SEQID NO: 1.

Exemplary codon-optimized human FXN coding sequence (SEQ ID NO: 1)ATGTGGACACTGGGGAGAAGGGCCGTGGCTGGACTGCTGGCTTCTCCATCTCCAGCCCAGGCCCAGACCCTGACCAGAGTGCCTAGACCTGCCGAACTGGCCCCTCTGTGTGGCAGAAGAGGCCTGAGAACCGACATCGACGCCACCTGTACCCCCAGAAGGGCCAGCAGCAATCAGCGGGGCCTGAATCAGATCTGGAACGTGAAGAAACAGAGCGTGTACCTGATGAACCTGAGAAAGAGCGGCACCCTGGGCCACCCTGGAAGCCTGGATGAGACAACCTACGAGCGGCTGGCCGAGGAAACCCTGGATTCCCTGGCCGAGTTCTTCGAGGACCTGGCCGACAAGCCCTACACCTTCGAGGATTACGACGTGTCCTTCGGCAGCGGCGTGCTGACAGTGAAGCTGGGCGGAGATCTGGGCACCTACGTGATCAACAAGCAGACCCCCAACAAACAGATCTGGCTGAGCAGCCCCAGCAGCGGCCCCAAGAGATACGATTGGACCGGCAAGAACTGGGTGTTCAGCCACGACGGCGTGTCCCTGCATGAGCTGCTGGCTGCCGAGCTGACCAAGGCCCTGAAAACAAAGCTGGACCTGAGCTGGCTGGCCTACAGCGGCAAAGATGCCATCGATATCCCCAGCCCCGTTTTAAGGACATTAAAAGCTATCAGGCCAAGACCCCAGCTTCATTATGCAGCTGAGGTCTGTTTTTTGTTGTTGTTGTTGTTTATTTTTTTTATTCCTGCTTTTGAGGACAGTTGGGCTATGTGTCACAGCTCTGTAGAAAGAATGTGTTGCCTCCTACCTTGCCCCCAAGTTCTGATTTTTAATTTCTATGGAAGATTTTTTGGATTGTCGGATTTCCTCCCTCACATGATACCCCTTATCTTTTATAATGTCTTATGCCTATACCTGAATATAACAACCTTTAAAAAAGCAAAATAA

In some embodiments, the promoter is a Desmin promoter, or a fragment orvariant thereof that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98%,99%, 100%, or more of the activity (e.g., promotion of transcription ofa gene, such as in a neuronal or muscle cell) of a wild-type humanDesmin promoter. In some embodiments, the promoter comprises two or morefragments of a Desmin promoter (e.g., an enhancer fragment and a basalpromoter fragment, which may be fused together optionally with a spaccrsequence). The fragment(s) may be 10, 20, 30, 40, 50, 60, 70, 80, 90,100, 120, 150, 200, 250, 500, 1000 or more nucleotides shorter than awild-type human Desmin promoter. In some embodiments, the Desminpromoter comprises one or more of (e.g., one, two, three, or four of) aMEF2 responsive element, a MyoD E-box, a CACC box and a TATA box. Insome embodiments, the promoter has a sequence that is at least 80%, 85%,90%, 95%, 96%, 97%, 98%, 99%, 100% identical to the sequence of SEQ IDNO: 2. In some embodiments, the promoter is a Desmin promoter having thesequence of SEQ ID NO: 2.

Exemplary Desmin promoter sequence (potential MEF2 responsive element(with 9 bp AT-rick core) at position 65-73, MyoD E-box at position97-102, CACC box at position 160-163 (binds nuclear factors present incardiac and skeletal muscle myocytes), CACC box at position 176-179,CACC box at position 179-182, CACC box at position 253-256, MyoD E-boxat position 270-275, CACC box at position 338-341, MyoD E-box atposition 542-547, TATA box at position 585-590, and CACC box at position696-699).

(SEQ ID NO: 2) GATCTTACCCCCTGCCCCCCACAGCTCCTCTCCTGTGCCTTGTTTCCCAGCCATGCGTTCTCCTCTATAAATACCCGCTCTGGTATTTGGGGTTGGCAGCTGTTGCTGCCAGGGAGATGGTTGGGTTGACATGCGGCTCCTGACAAAACACAAACCCCTGGTGTGTGTCGGCGTGGGTGGTGTGAGTAGGGGGATGAATCACCCAGGGGGCGGGGGACCCAGGGGGCAGGAGCCACACAAAGTCTGTGCGGGGGTGGGAGCGCACATAGCAATTGGAAACTGAAAGCTTATCAGACCCTTTCTGGAAATCAGCCCACTGTTTATAAACTTGAGGCCCCACCCTCGAGATAACCAGGGCTGAAAGAGGCCCGCCTGGGGGCTGGAGACATGCTTGCTGCCTGCCCTGGCGAAGGATTGGCAGGCTTGCCCGTCACAGGACCCCCGCTGGCTGACTCAGGGGCGCAGGCCTCTTGCGGGGGAGCTGGCCTCCCCGCCCCCACGGCCACGGGCCGCCCTTTCCTGGCAGGACAGCGGGATCTTGCAGCTGTCACCCCAGGGGAGGCGGGGCCTGATGTCAGGAGCCATACAAATAGTGCCGACGGCTGGGGGCCCTGTCTCCCCTCGCCGCATCCACTCTCCGGCCGGCCGCCTGTCCGCCGCCTCCTCCGTGCGCCCGCCAGCCTCGCCCGCGCCGTCACCGTGAGGCACTGGG

In some embodiments, the promoter is a Chicken β-actin (CBA) promoter,or a fragment or variant thereof that has at least 80%, 85%, 90%, 95%,96%, 97%, 98%, 99%, 100%, or more of the activity (e.g., promotion oftranscription of a gene, such as in a neuronal or muscle cell) of awild-type full-length promoter. In some embodiments, the promotercomprises two or more fragments of a CBA promoter (e.g., an enhancerfragment and a basal promoter fragment, which may be fused togetheroptionally with a spacer sequence). The fragment(s) may be 10, 20, 30,40, 50, 60, 70, 80, 90, 100, 120, 150, 200, 250, 500, 1000 or morenucleotides shorter than the full-length CBA promoter. In someembodiments, the CBA promoter comprises one or more of (e.g., one, two,three, or four of) a MEF2 responsive element, a MyoD E-box, a CACC boxand a TATA box. In some embodiments, the promoter has a sequence that isat least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 100% identical to thesequence of SEQ ID NO: 7. In some embodiments, the promoter is a CBApromoter having the sequence of SEQ ID NO: 7.

Exemplary CBA promoter sequence (SEQ ID NO: 7)ctagatctgaattcggtaccctagttattaatagtaatcaattacggggtcattagttcatagcccatatatggagttccgcgttacataacttacggtaaatggcccgcctggctgaccgcccaacgacccccgcccattgacgtcaataatgacgtatgttcccatagtaacgccaatagggactttccattgacgtcaatgggtggactatttacggtaaactgcccacttggcagtacatcaagtgtatcatatgccaagtacgccccctattgacgtcaatgacggtaaatggcccgcctggcattatgcccagtacatgaccttatgggactttcctacttggcagtacatctacgtattagtcatcgctattaccatggtcgaggtgagccccacgttctgcttcactctccccatctcccccccctccccacccccaattttgtatttatttattttttaattattttgtgcagcgatgggggcggggggggggggggggcgcgcgccaggcggggcggggcggggcgaggggcggggcggggcgaggcggagaggtgcggcggcagccaatcagagcggcgcgctccgaaagtttccttttatggcgaggcggcggcggcggcggccctataaaaagcgaagcgcgcggcgggcgggagtcgctgcgacgctgccttcgccccgtgccccgctccgccgccgcctcgcgccgcccgccccggctctgactgaccgcgttactcccacaggtgagcgggcgggacggcccttctcctccgggctgtaattagcgcttggtttaatgacggcttgtttcttttctgtggctgcgtgaaagccttgaggggctccgggagggccctttgtgcgggggggagcggctcggggggtgcgtgcgtgtgtgtgtgcgtggggagcgccgcgtgcggcccgcgctgcccggcggctgtgagcgctgcgggcgcggcgcggggctttgtgcgctccgcagtgtgcgcgaggggagcgcggccgggggcggtgccccgcggtgcggggggggctgcgaggggaacaaaggctgcgtgcggggtgtgtgcgtgggggggtgagcagggggtgtgggcgcggcggtcgggctgtaacccccccctgcacccccctccccgagttgctgagcacggcccggcttcgggtgcggggctccgtacggggcgtggcgcggggctcgccgtgccgggcggggggtggcggcaggtgggggtgccgggcggggcggggccgcctcgggccggggagggctcgggggaggggcgcggcggcccccggagcgccggcggctgtcgaggcgcggcgagccgcagccattgccttttatggtaatcgtgcgagagggcgcagggacttcctttgtcccaaatctgtgcggagccgaaatctgggaggcgccgccgcaccccctctagcgggcgcggggcgaagcggtgcggcgccggcaggaaggaaatgggcggggagggccttcgtgcgtcgccgcgccgccgtccccttctccctctccagcctcggggctgtccgcggggggacggctgccttcgggggggacggggcagggcggggttcggcttctggcgtgtgaccggcggctctagagcctctgctaaccatgttcatgccttcttctttttcctacagctcctgggcaacgtgctggttattgtgctgtctcatcattttggcaaagaattcctcgaagatccgaaggggttcaagcttaaaaa

In some embodiments, the promoter is a human FXN promoter (hFXNPropromoter), or a fragment or variant thereof that has at least 80%, 85%,90%, 95%, 96%, 97%, 98%, 99%, 100%, or more of the activity (e.g.,promotion of transcription of a gene, such as in a neuronal or musclecell) of a wild-type hFXNPro. In some embodiments, the promotercomprises two or more fragments of a hFXNPro (e.g., an enhancer fragmentand a basal promoter fragment, which may be fused together optionallywith a spacer sequence). The fragment(s) may be 10, 20, 30, 40, 50, 60,70, 80, 90, 100, 120, 150, 200, 250, 500, 1000 or more nucleotidesshorter than a wild-type hFXNPro. In some embodiments, the hFXNProcomprises one or more of (e.g., one, two, three, or four of) a MEF2responsive element, a MyoD E-box, a CACC box and a TATA box. In someembodiments, the promoter has a sequence that is at least 80%9, 85%,90%, 95%, 96%, 97%, 98%, 99%, 100% identical to the sequence of SEQ IDNO: 8. In some embodiments, the promoter is a hFXNPro having thesequence of SEQ ID NO: 8.

Exemplary hFXNPro sequence (SEQ ID NO: 8)AAGAAAACTTTCACAATTTGCATCCCTTTGTAATATGTAACAGAAATAAAATTCTCTTTTAAAATCTATCAACAATAGCCAAGGCACGGTGGCTCACGCCTGTCGTCTCAGCACTTTGTGAGGCCCAGGCGGGCAGATCGTTTGAGCCTAGAAGTTCAAGACCACCCTGGGCAACATAGCGAAACCCCCTTTCTACAAAAAATACAAAAACTAGCTGGGTGTGGTGGTGCACACCTGTAGTCCCAGCTACTTGGAAGGCTGAAATGGGAAGACTGCTTGAGCCCGGGAGGGAGAAGTTGCAGTAAGCCAGGACCACACGACTGCACTCCAGCCTGGGCAACAGAGTGAGACTCTGTCTCAAACAAACAATAAATGAGCCCGGGTGGATCACGAGGTCAGTAGATCGAGACCATCCTGGCTAACACGGTGAAACCCGTCTCTACTAAAAAAAAAAAAAAATACAAAAAATTAGCCAGGCATGGTGGCGGGCGCCTGTAGTCCCAGTTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAAACCGGGAGGCAGAGCTTGCAGTGAGCCGAGATCGCACCACTGCCCTCCAGCCTGGGCGACAGAGCGAGACTCCGTCTCAATCAATCAATCAATCAATAAAATCTATTAACAATATTTATTGTGCACTTAACAGGAACATGCCCTGTCCAAAAAAAACTTTACAGGGCTTAACTCATTTTATCCTTACCACAATCCTATGAAGTAGGAACTTTTATAAAACGCATTTTATAAACAAGGCACAGAGAGGTTAATTAACTTGCCCTCTGGTCACACAGCTAGGAAGTGGGCAGAGTACAGATTTACACAAGGCATCCGTCTCCTGGCCCCACATACCCAACTGCTGTAAACCCATACCGGCGGCCAAGCAGCCTCAATTTGTGCATGCACCCACTTCCCAGCAAGACAGCAGCTCCCAAGTTCCTCCTGTTTAGAATTTTAGAAGCGGCGGGCCACCAGGCTGCagtctcccttgggtcaggggtcctggttgcactccgtgctttgcacaaagcaggctctccatttttgttaaatgcacgaatagtgctaagctgggaagttcttcctgaggtctaacctctagctgctcccccacagaagagtgcctgcggccagtggccaccaggggtcgccgcagcacccagcgctggagggcggagcg ggcggcagacccggagcagc

In some embodiments, the promoter has a sequence that is at least 80%,85%, 90%, 95%, 96%, 97%, 98%, 99%, 100% identical to the sequenceidentified as nucleotides 2312-2404 of GenBank accession No.NC_001510.1.

In some embodiments, the FXN 3′ untranslated region (UTR) is a truncatedFXN 3′ UTR. In some embodiments, the truncated FXN 3′ UTR is a truncatedhuman FXN 3′ UTR. In some embodiments, the truncated FXN 3′ UTR is atleast 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000 ormore nucleotides shorter than a wild-type FXN 3′ UTR. In someembodiments, the 3′ UTR is truncated (e.g., by at least 100, 200, 300,400, 500, 600, 700, 800, 900, 1000, 1500, 2000 or more nucleotides) andthe truncated sequence has at least 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, or 99% sequence identity with the corresponding sequencein a wild-type FXN 3′ UTR. In some embodiments, the 3′ UTR is truncatedrelative to the below wild-type FXN 3′ UTR. In some embodiments, thetruncated 3′ UTR is no more than 2000, 1900, 1800, 1700, 1600, 1500,1400, 1300, 1200, 1100, or 1000 nucleotides in length.

Exemplary human FXN 3′ UTR (SEQ ID NO: 9)   1 ACTAGTGCCA CCATGTGGAC ACTGGGGAGA AGGGCCGTGG CTGGACTGCT GGCTTCTCCA  61 TCTCCAGCCC AGGCCCAGAC CCTGACCAGA GTGCCTAGAC CTGCCGAACT GGCCCCTCTG 121 TGTGGCAGAA GAGGCCTGAG AACCGACATC GACGCCACCT GTACCCCCAG AAGGGCCAGC 181 AGCAATCAGC GGGGCCTGAA TCAGATCTGG AACGTGAAGA AACAGAGCGT GTACCTGATG 241 AACCTGAGAA AGAGCGGCAC CCTGGGCCAC CCTGGAAGCC TGGATGAGAC AACCTACGAG 301 CGGCTGGCCG AGGAAACCCT GGATTCCCTG GCCGAGTTCT TCGAGGACCT GGCCGACAAG 361 CCCTACACCT TCGAGGATTA CGACGTGTCC TTCGGCAGCG GCGTGCTGAC AGTGAAGCTG 421 GGCGGAGATC TGGGCACCTA CGTGATCAAC AAGCAGACCC CCAACAAACA GATCTGGCTG 481 AGCAGCCCCA GCAGCGGCCC CAAGAGATAC GATTGGACCG GCAAGAACTG GGTGTTCAGC 541 CACGACGGCG TGTCCCTGCA TGAGCTGCTG GCTGCCGAGC TGACCAAGGC CCTGAAAACA 601 AAGCTGGACC TGAGCTGGCT GGCCTACAGC GGCAAAGATG CCATCGATAT CCCCAGCCCC 661 GTTTTAAGGA CATTAAAAGC TATCAGGCCA AGACCCCAGC TTCATTATGC AGCTGAGGTC 721 TGTTTTTTGT TGTTGTTGTT GTTTATTTTT TTTATTCCTG CTTTTGAGGA CAGTTGGGCT 781 ATGTGTCACA GCTCTGTAGA AAGAATGTGT TGCCTCCTAC CTTGCCCCCA AGTTCTGATT 841 TTTAATTTCT ATGGAAGATT TTTTGGATTG TCGGATTTCC TCCCTCACAT GATACCCCTT 901 ATCTTTTATA ATGTCTTATG CCTATACCTG AATATAACAA CCTTTAAAAA AGCAAAATAA 961 TAAGAAGGAA AAATTCCAGG AGGGAAAATG AATTGTCTTC ACTCTTCATT CTTTGAAGGA1021 TTTACTGCAA GAAGTACATG AAGAGCAGCT GGTCAACCTG CTCACTGTTC TATCTCCAAA1081 TGAGACACAT TAAAGGGTAG CCTACAAATG TTTTCAGGCT TCTTTCAAAG TGTAAGCACT1141 TCTGAGCTCT TTAGCATTGA AGTGTCGAAA GCAACTCACA CGGGAAGATC ATTTCTTATT1201 TGTGCTCTGT GACTGCCAAG GTGTGGCCTG CACTGGGTTG TCCAGGGAGA CATGCATCTA1261 GTGCTGTTTC TCCCACATAT TCACATACGT GTCTGTGTGT ATATATATTT TTTCAATTTA1321 AAGGTTAGTA TGGAATCAGC TGCTACAAGA ATGCAAAAAA TCTTCCAAAG ACAAGAAAAG1381 AGGAAAAAAA GCCGTTTTCA TGAGCTGAGT GATGTAGCGT AACAAACAAA ATCATGGAGC1441 TGAGGAGGTG CCTTGTAAAC ATGAAGGGGC AGATAAAGGA AGGAGATACT CATGTTGATA1501 AAGAGAGCCC TGGTCCTAGA CATAGTTCAG CCACAAAGTA GTTGTCCCTT TGTGGACAAG1561 TTTCCCAAAT TCCCTGGACC TCTGCTTCCC CATCTGTTAA ATGAGAGAAT AGAGTATGGT1621 TGATTCCCAG CATTCAGTGG TCCTGTCAAG CAACCTAACA GGCTAGTTCT AATTCCCTAT1681 TGGGTAGATG AGGGGATGAC AAAGAACAGT TTTTAAGCTA TATAGGAAAC ATTGTTATTG1741 GTGTTGCCCT ATCGTGATTT CAGTTGAATT CATGTGAAAA TAATAGCCAT CCTTGGCCTG1801 GCGCGGTGGC TCACACCTGT AATCCCAGCA CTTTTGGAGG CCAAGGTGGG TGGATCACCT1861 GAGGTCAGGA GTTCAAGACC AGCCTGGCCA ACATGATGAA ACCCCGTCTC TACTAAAAAT1921 ACAAAAAATT AGCCGGGCAT GATGGCAGGT GCCTGTAATC CCAGCTACTT GGGAGGCTGA1981 AGCGGAAGAA TCGCTTGAAC CCAGAGGTGG AGGTTGCAGT GAGCCGAGAT CGTGCCATTG2041 CACTGTAACC TGGGTGACTG AGCAAAACTC TGTCTCAAAA TAATAATAAC AATATAATAA2101 TAATAATACC CATCCTTTAT TGTACCCTTA CTGGGTTAAT CGTATTATAC CACATTACCT2161 CATTTTAATT TTTACTGACC TGCACTTTAT ACAAAGCAAC AAGCCTCCAG GACATTAAAA2221 TTCATGCAAA GTTATGCTCA TGTTATATTA TTTTCTTACT TAAAGAAGGA TTTATTAGTG2281 GCTGGGCATG GTGGCGTGCA CCTGTAATCC CAGGTACTCA GGAGGCTGAG ACGGGAGAAT2341 TGCTTGACCC CAGGCGGAGG AGGTTACAGT GAGTCGAGAT CGTACCTGAG CGACAGAGCG2401 AGACTCCGTC TCAAAAAAAA AAAAAAGGAG GGTTTATTAA TGAGAACTTT GGTCGAC

In some embodiments, the truncated FXN 3′ UTR has the sequence of SEQ IDNO: 3.

Exemplary truncated FXN 3′ UTR (SEQ ID NO: 3)AAGAAGGAAAAATTCCAGGAGGGAAAATGAATTGTCTTCACTCTTCATTCTTTGAAGGATTTACTGCAAGAAGTACATGAAGAGCAGCTGGTCAACCTGCTCACTGTTCTATCTCCAAATGAGACACATTAAAGGGTAGCCTACAAATGTTTTCAGGCTTCTTTCAAAGTGTAAGCACTTCTGAGCTCTTTAGCATTGAAGTGTCGAAAGCAACTCACACGGGAAGATCATTTCTTATTTGTGCTCTGTGACTGCCAAGGTGTGGCCTGCACTGGGTTGTCCAGGGAGACATGCATCTAGTGCTGTTTCTCCCACATATTCACATACGTGTCTGTGTGTATATATATTTTTTCAATTTAAAGGTTAGTATGGAATCAGCTGCTACAAGAATGCAAAAAATCTTCCAAAGACAAGAAAAGAGGAAAAAAAGCCGTTTTCATGAGCTGAGTGATGTAGCGTAACAAACAAAATCATGGAGCTGAGGAGGTGCCTTGTAAACATGAAGGGGCAGATAAAGGAAGGAGATACTCATGTTGATAAAGAGAGCCCTGGTCCTAGACATAGTTCAGCCACAAAGTAGTTGTCCCTTTGTGGACAAGTTTCCCAAATTCCCTGGACCTCTGCTTCCCCATCTGTTAAATGAGAGAATAGAGTATGGTTGATTCCCAGCATTCAGTGGTCCTGTCAAGCAACCTAACAGGCTAGTTCTAATTCCCTATTGGGTAGATGAGGGGATGACAAAGAACAGTTTTTAAGCTATATAGGAAACATTGTTATTGGTGTTGCCCTATCGTGATTTCAGTTGAATTCATGTGAAAATAATAGCCATCCTTGGCCTGGCGCGGTGCCTCACACCTGTAATCCCAGCACTTTTGGAGGCCAAGGTGGGTGGATCACCTGAGGTCAGGAGTTCAAGACCAGCCTGGCCAACATGATGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCATGATGGCAGGTGCCTGTAATCCCAGCTACTTGGGAGGCTGAAGCGGAAGAATCGCTTGAACCCAGAGGTGGAGGTTGCAGTGAGCCGAGATCGTGCCATTGCACTGTAACCTGGGTGACTGAGCAAAACTCTGTCTCAAAATAATAATAACAATATAATAATAATAATAGCCATCCTTTATTGTACCCTTACTGGGTTAATCGTATTATACCACATTACCTCATTTTAATTTTTACTGACCTGCACTTTATACAAAGCAACAAGCCTCCAGGACATTAAAATTCATGCAAAGTTATGCTCATGTTATATTATTTTCTTACTTAAAGAAGGATTTATTAGTGGCTGGGCATGGTGGCGTGCACCTGTAATCCCAGGTACTCAGGAGGCTGAGACGGGAGAATTGCTTGACCCCAGGCGGAGGAGGTTACAGTGAGTCGAGATCGTACCTGAGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAGGAGGGTTTATTAATGAGAAGTT TG

In some embodiments, the expression construct further contains a nucleicacid segment that encode a polyadenylation signal. In some embodiments,the nucleic acid segment is positioned 3′ to the FXN 3′ UTR in theexpression construct.

In some embodiments, the expression construct comprises the sequence ofSEQ ID NO: 4 (or a portion thereof comprising a gene of interest underthe control of a promoter of interest, optionally flanked by ITRsequences).

Exemplary expression construct (SEQ ID NO: 4)GATCTTACCCCCTGCCCCCCACAGCTCCTCTCCTGTGCCTTGTTTCCCAGCCATGCGTTCTCCTCTATAAATACCCGCTCTGGTATTTGGGGTTGGCAGCTGTTGCTGCCAGGGAGATGGTTGGGTTGACATGCGGCTCCTGACAAAACACAAACCCCTGGTGTGTGTGGGCGTGGGTGGTGTGAGTAGGGGGATGAATCAGGGAGGGGGCGGGGGACCCAGGGGGCAGGAGCCACACAAAGTCTGTGCGGGGGTGGGAGCGCACATAGCAATTGGAAACTGAAAGCTTATCAGACCCTTTCTGGAAATCAGCCCACTGTTTATAAACTTGAGGCCCCACCCTCGAGATAACCAGGGCTGAAAGAGGCCCGCCTGGGGGCTGGAGACATGCTTGCTGCCTGCCCTGGCGAAGGATTGGCAGGCTTGCCCGTCACAGGACCCCCGCTGGCTGACTCAGGGGCGCAGGCCTCTTGCGGGGGAGCTCCCCTCCCCGCCCCCACGCCCACGGGCCGCCCTTTCCTGGCAGGACAGCGGGATCTTGCAGCTGTCAGGGGAGGGGAGGCGGGGGCTGATGTCAGGAGGGATACAAATAGTGCCGACGGCTGGGGGCCCTGTCTCCCCTCGCCGCATCCACTCTCCGGCCGGCCGCCTGTCCGCCGCCTCCTCCGTGCGCCCGCCAGCCTCGCCCGCGCCGTCACCGTGAGGCACTGGGCAGGTAAGTATCAAAGTATCAAGGTTACAAGACAGGTTTAAGGAGACCAATAGAAACTGGGCTTGTCGAGACAGAGAAGACTCTTGCGTTTCTGATAGGCACCTATTGGTCTTACTGACATCCACTTTGCCTTTCTCTCCACAGGCTAGCCTCGAGAATTCACGCGTGGTACCTCTAGAGTCGACCGATATCACTAGTGCCACCATGTGGACACTGGGGAGAAGGGCCGTGGCTGGACTGCTGGCTTCTCCATCTCCAGCCCAGGCCCAGACCCTGACCAGAGTGCCTAGACCTGCCGAACTGGCCCCTCTGTGTGGCAGAAGAGGCCTGAGAACCGACATCGACGCCACCTGTACCCCCAGAAGGGCCAGCAGCAATCAGCGGGGCCTGAATCAGATCTGGAACGTGAAGAAACAGAGCGTGTACCTGATGAACCTGAGAAAGAGCGGCACCCTGGGCCACCCTGGAAGCCTGGATGAGACAACCTACGAGCGGCTGGCCGAGGAAACCCTGGATTCCCTGGCCGAGTTCTTCGAGGACCTGGCCGACAAGCCCTACACCTTCGAGGATTACGACGTGTCCTTCGGCAGCGGCGTGCTGACAGTGAAGCTGGGCGGAGATCTGGGCACCTACGTGATCAACAAGCAGACCCCCAACAAACAGATCTGGCTGAGCAGCCCCAGCAGCGGCCCCAAGAGATACGATTGGACCGGCAAGAACTGGGTGTTCAGCCACGACGGCGTGTCCCTGCATGAGCTGCTGGCTGCCGAGCTGACCAAGGCCCTGAAAACAAAGCTGGACCTGAGCTGGCTGGCCTACAGCGGCAAAGATGCCATCGATATCCCCAGCCCCGTTTTAAGGACATTAAAAGCTATCAGGCCAAGACCCCAGCTTCATTATGCAGCTGAGGTCTGTTTTTTGTTGTTGTTGTTGTTTATTTTTTTTATTCCTGCTTTTGAGGACAGTTGGGCTATGTGTCACAGCTCTGTAGAAAGAATGTGTTGCCTCCTACCTTGCCCCCAAGTTCTGATTTTTAATTTCTATGGAAGATTTTTTGGATTGTCGGATTTCCTCCCTCACATGATACCCCTTATCTTTTATAATGTCTTATGCCTATACCTGAATATAACAACCTTTAAAAAAGCAAAATAATAAGAAGGAAAAATTCCAGGAGGGAAAATGAATTGTCTTCACTCTTCATTCTTTGAAGGATTTACTGCAAGAAGTACATGAAGAGCAGCTGGTCAACCTGCTCACTGTTCTATCTCCAAATGAGACACATTAAAGGGTAGCCTACAAATGTTTTCAGGCTTCTTTCAAAGTGTAAGCACTTCTGAGCTCTTTAGCATTGAAGTGTCGAAAGCAACTCACACGGGAAGATCATTTCTTATTTGTGCTCTGTGACTGCCAAGGTGTGGCCTGCACTGGGTTGTCCAGGGAGACATGCATCTAGTGCTGTTTCTCCCACATATTCACATACGTGTCTGTGTGTATATATATTTTTTCAATTTAAAGGTTAGTATGGAATCAGCTGCTACAAGAATGCAAAAAATCTTCCAAAGACAAGAAAAGAGGAAAAAAAGCCGTTTTCATGAGCTGAGTGATGTAGCGTAACAAACAAAATCATGGAGCTGAGGAGGTGCCTTGTAAACATGAAGGGGCAGATAAAGGAAGGAGATACTCATGTTGATAAAGAGAGCCCTGGTCCTAGACATAGTTCAGCCACAAAGTAGTTGTCCCTTTGTGGACAAGTTTCCCAAATTCCCTGGACCTCTGCTTCCCCATCTGTTAAATGAGAGAATAGAGTATGGTTGATTCCCAGCATTCAGTGGTCCTGTCAAGCAACCTAACAGGCTAGTTCTAATTCCCTATTGGGTAGATGAGGGGATGACAAAGAACAGTTTTTAAGCTATATAGGAAACATTGTTATTGGTGTTGCCCTATCGTGATTTCAGTTGAATTCATGTGAAAATAATAGCCATCCTTGGCCTGGCGCGGTGGCTCACACCTGTAATCCCAGCACTTTTGGAGGCCAAGGTGGGTGGATCACCTGAGGTCAGGAGTTCAAGACCAGCCTGGCCAACATGATGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCATGATGGCAGGTGCCTGTAATCCCAGCTACTTGGGAGGCTGAAGCGGAAGAATCGCTTGAACCCAGAGGTGGAGGTTGCAGTGAGCCGAGATCGTGCCATTGCACTGTAACCTGGGTGACTGAGCAAAACTCTGTCTCAAAATAATAATAACAATATAATAATAATAATAGCCATCCTTTATTGTACCCTTACTGGGTTAATCGTATTATACCACATTACCTCATTTTAATTTTTACTGACCTGCACTTTATACAAAGCAACAAGCCTCCAGGACATTAAAATTCATGCAAAGTTATGCTCATGTTATATTATTTTCTTACTTAAAGAAGGATTTATTAGTGGCTGGGCATGGTGGCGTCCACCTGTAATCCCAGGTACTCAGGAGGCTGAGACGGGAGAATTGCTTGACCCCAGGCGGAGGAGGTTACAGTGAGTCGAGATCGTACCTGAGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAGGAGGGTTTATTAATGAGAAGTTTGGTCGACTAGAGCGGCCGCTTCGAGCAGACATGATAAGATACATTGATGAGTTTGGACAAACCACAACTAGAATGCAGTGAAAAAAATGCTTTATTTGTGAAATTTGTGATGCTATTGCTTTATTTGTAACCATTATAAGCTGCAATAAACAAGTTAACAACAACAATTGCATTCATTTTATGTTTCAGGTTCAGGGGGAGATGTGGGAGGTTTTTTAAAGCAAGTAAAACCTCTACAAATGTGGT A

In some embodiments, the nucleic acid is a plasmid. In some embodiments,the nucleic acid comprises or consists of the sequence of SEQ ID NO 5.

Exemplary plasmid sequence (SEQ ID NO: 5)CTGCAGGGGGGGGGGGGGGGGGGTTGGCCACTCCCTCTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGCGACCAAAGGTCGCCCGACGCCCGGGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGGAGTGGCCAACTCCATCACTAGGGGTTCCTCAGATCTTACCCCCTGCCCCCCACAGCTCCTCTCCTGTGCCTTGTTTCCCAGCCATGCGTTCTCCTCTATAAATACCCGCTCTGGTATTTGGGGTTGGCAGCTGTTGCTGCCAGGGAGATGGTTGGGTTGACATGCGGCTCCTGACAAAACACAAACCCCTGGTGTGTGTGGGCGTGGGTGGTGTGAGTAGGGGGATGAATCAGGGAGGGGGCGGGGGACCCAGGGGGCAGGAGCCACACAAAGTCTGTGCGGGGGTGGGAGCGCACATAGCAATTGGAAACTGAAAGCTTATCAGACCCTTTCTGGAAATCAGCCCACTGTTTATAAACTTGAGGCCCCACCCTCGAGATAACCAGGGCTGAAAGAGGCCCGCCTGGGGGCTGGAGACATCCTTGCTGCCTGCCCTCCCGAAGGATTGGCAGGCTTGCCCGTCACAGGACCCCCGCTGGCTGACTCAGGGGCGCAGGCCTCTTGCGGGGGAGCTGGCCTCCCCGCCCCCACGGCCACGGGCCGCCCTTTCCTGGCAGGACAGCGGGATCTTGCAGCTGTCAGGGGAGGGGAGGCGGGGGCTGATGTCAGGAGGGATACAAATAGTGCCGACGGCTGGGGGCCCTGTCTCCCCTCGCCGCATCCACTCTCCGGCCGGCCGCCTGTCCGCCGCCTCCTCCGTGCGCCCGCCAGCCTCGCCCGCGCCGTCACCGTGAGGCACTGGGCAGGTAAGTATCAAAGTATCAAGGTTACAAGACAGGTTTAAGGAGACCAATAGAAACTGGGCTTGTCGAGACAGAGAAGACTCTTGCGTTTCTGATAGGCACCTATTGGTCTTACTGACATCCACTTTGCCTTTCTCTCCACAGGCTAGCCTCGAGAATTCACGCGTGGTACCTCTAGAGTCGACCGATATCACTAGTGCCACCATGTGGACACTGGGGAGAAGGGCCGTGGCTGGACTGCTGGCTTCTCCATCTCCAGCCCAGGCCCAGACCCTGACCAGAGTGCCTAGACCTGCCGAACTGGCCCCTCTGTGTGGCAGAAGAGGCCTGAGAACCGACATCGACGCCACCTGTACCCCCAGAAGGGCCAGCAGCAATCAGCGGGGCCTGAATCAGATCTGGAACGTGAAGAAACAGAGCGTGTACCTGATGAACCTGAGAAAGAGCGGCACCCTGGGCCACCCTGGAAGCCTGGATGAGACAACCTACGAGCGGCTGGCCGAGGAAACCCTGGATTCCCTGGCCGAGTTCTTCGAGGACCTGGCCGACAAGCCCTACACCTTCGAGGATTACGACGTGTCCTTCGGCAGCGGCGTGCTGACAGTGAAGCTGGGCGGAGATCTGGGCACCTACGTGATCAACAAGCAGACCCCCAACAAACAGATCTGGCTGAGCAGCCCCAGCAGCGGCCCCAAGAGATACGATTGGACCGGCAAGAACTGGGTGTTCAGCCACGACGGCGTGTCCCTGCATGAGCTGCTGGCTGCCGAGCTGACCAAGGCCCTGAAAACAAAGCTGGACCTGAGCTGGCTGGCCTACAGCGGCAAAGATGCCATCGATATCCCCAGCCCCGTTTTAAGGACATTAAAAGCTATCAGGCCAAGACCCCAGCTTCATTATGCAGCTGAGGTCTGTTTTTTGTTGTTGTTGTTGTTTATTTTTTTTATTCCTGCTTTTGAGGACAGTTGGGCTATGTGTCACAGCTCTGTAGAAAGAATGTGTTGCCTCCTACCTTGCCCCCAAGTTCTGATTTTTAATTTCTATGGAAGATTTTTTGGATTGTCGGATTTCCTCCCTCACATGATACCCCTTATCTTTTATAATGTCTTATGCCTATACCTGAATATAACAACCTTTAAAAAAGCAAAATAATAAGAAGGAAAAATTCCAGGAGGGAAAATGAATTGTCTTCACTCTTCATTCTTTGAAGGATTTACTGCAAGAAGTACATGAAGAGCAGCTGGTCAACCTGCTCACTGTTCTATCTCCAAATGAGACACATTAAAGGGTAGCCTACAAATGTTTTCAGGCTTCTTTCAAAGTGTAAGCACTTCTGAGCTCTTTAGCATTGAAGTGTCGAAAGCAACTCACACGGGAAGATCATTTCTTATTTGTGCTCTGTGACTGCCAAGGTGTGGCCTGCACTGGGTTGTCCAGGGAGACATGCATCTAGTGCTGTTTCTCCCACATATTCACATACGTGTCTGTGTGTATATATATTTTTTCAATTTAAAGGTTAGTATGGAATCAGCTGCTACAAGAATGCAAAAAATCTTCCAAAGACAAGAAAAGAGGAAAAAAAAGCCGTTTCATGAGCTGAGTGATGTAGCGTAACAAACAAAATCATGGAGCTGAGGAGGTGCCTTGTAAACATGAAGGGGCAGATAAAGGAAGGAGATACTCATGTTGATAAAGAGAGCCCTGGTCCTAGACATAGTTCAGCCACAAAGTAGTTGTCCCTTTGTGGACAAGTTTCCCAAATTCCCTGGACCTCTGCTTCCCCATCTGTTAAATGAGAGAATAGAGTATGGTTGATTCCCAGCATTCAGTGGTCCTGTCAAGCAACCTAACAGGCTAGTTCTAATTCCCTATTGGGTAGATGAGGGGATGACAAAGAACAGTTTTTAAGCTATATAGGAAACATTGTTATTGGTGTTGCCCTATCGTGATTTCAGTTGAATTCATGTGAAAATAATAGCCATCCTTGGCCTGGCGCGGTGGCTCACACCTGTAATCCCAGCACTTTTGGAGGCCAAGGTGGGTGGATCACCTGAGGTCAGGAGTTCAAGACCAGCCTGGCCAACATGATGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCATGATGGCAGGTGCCTGTAATCCCAGCTACTTGGGAGGCTGAAGCGGAAGAATCGCTTGAACCCAGAGGTGGAGGTTGCAGTGAGCCGAGATCGTGCCATTGCACTGTAACCTGGGTGACTGAGCAAAACTCTGTCTCAAAATAATAATAACAATATAATAATAATAATAGCCATCCTTTATTGTACCCTTACTGGGTTAATCGTATTATACCACATTACCTCATTTTAATTTTTACTGACCTGCACTTTATACAAAGCAACAACCCTCCAGGACATTAAAATTCATGCAAAGTTATGCTCATGTTATATTATTTTCTTACTTAAAGAAGGATTTATTAGTGGCTGGGCATGGTGGCGTGCACCTGTAATCCCAGGTACTCAGGAGGCTGAGACGGGAGAATTGCTTGACCCCAGGCGGAGGAGGTTACAGTGAGTCGAGATCGTACCTGAGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAGGAGGGTTTATTAATGAGAAGTTTGGTCGACTAGAGCGGCCGCTTCGAGCAGACATGATAAGATACATTGATGAGTTTGGACAAACCACAACTAGAATGCAGTGAAAAAAATGCTTTATTTGTGAAATTTGTGATGCTATTGCTTTATTTGTAACCATTATAAGCTGCAATAAACAAGTTAACAACAACAATTGCATTCATTTTATGTTTCAGGTTCAGGGGGAGATGTGGGAGGTTTTTTAAAGCAAGTAAAACCTCTACAAATGTGGTAAAATCGATAAGGATCTAGGAACCCCTAGTGATGGAGTTGGCCACTCCCTCTCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGGCGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGGAGTGGCCAACCCCCCCCCCCCCCCCCCCGCAGCCTGGCGTAATAGCGAAGAGGCCCGCACCGATCGCCCTTCCCAACAGTTGCGTAGCCTGAATGGCGAATGGCGCGACGCGCCCTGTAGCGGCGCATTAAGCGCGGCGGGTGTGGTGGTTACGCGCAGCGTGACCGCTACACTTGCCAGCGCCCTAGCGCCCGCTCCTTTCGCTTTCTTCCCTTCCTTTCTCGCCACGTTCGCCGGCTTTCCCCGTCAAGCTCTAAATCGGGGGCTCCCTTTAGGGTTCCGATTTAGTGCTTTACGGCACCTCGACCCCAAAAAACTTGATTAGGGTGATGGTTCACGTAGTGGGCCATCGCCCTGATAGACGGTTTTTCGCCCTTTGACGTTGGAGTCCACGTTCTTTAATAGTGGACTCTTGTTCCAAACTGGAACAACACTCAACCCTATCTCGGTCTATTCTTTTGATTTATAAGGGATTTTGCCGATTTCGGCCTATTGGTTAAAAAATGAGCTGATTTAACAAAAATTTAACGCGAATTTTAACAAAATATTAACGTTTACAATTTCCTGATGCGGTATTTTCTCCTTACGCATCTGTGCGGTATTTCACACCGCATATGGTGCACTCTCAGTACAATCTGCTCTGATGCCGCATAGTTAAGCCAGCCCCGACACCCGCCAACACCCGCTGACGCGCCCTGACGGGCTTGTCTGCTCCCGGCATCCGCTTACAGACAAGCTGTGACCGTCTCCGGGAGCTGCATGTGTCAGAGGTTTTCACCGTCATCACCGAAACGCGCGAGACGAAAGGGCCTCGTGATACGCCTATTTTTATAGGTTAATGTCATGATAATAATGGTTTCTTAGACGTCAGGTGGCACTTTTCGGGGAAATGTGCGCGGAACCCCTATTTGTTTATTTTTCTAAATACATTCAAATATGTATCCGCTCATGAGACAATAACCCTGATAAATGCTTCAATAATATTGAAAAAGGAAGAGTATGAGTATTCAACATTTCCGTGTCGCCCTTATTCCCTTTTTTGCGGCATTTTGCCTTCCTGTTTTTGCTCACCCAGAAACGCTGGTGAAAGTAAAAGATGCTGAAGATCAGTTGGGTGCACGAGTGGGTTACATCGAACTGGATCTCAACAGCGGTAAGATCCTTGAGAGTTTTCGCCCCGAAGAACGTTTTCCAATGATGAGCACTTTTAAAGTTCTGCTATGTGGCGCGGTATTATCCCGTATTGACGCCGGGCAAGAGCAACTCGGTCGCCGCATACACTATTCTCAGAATGACTTGGTTGAGTACTCACCAGTCACAGAAAAGCATCTTACGGATGGCATGACAGTAAGAGAATTATGCAGTGCTGCCATAACCATGAGTGATAACACTGCGGCCAACTTACTTCTGACAACGATCGGAGGACCGAAGGAGCTAACCGCTTTTTTGCACAACATGGGGGATCATGTAACTCGCCTTGATCGTTGGGAACCGGAGCTGAATGAAGCCATACCAAACGACGAGCGTGACACCACGATGCCTGTAGCAATGGCAACAACGTTGCGCAAACTATTAACTGGCGAACTACTTACTCTAGCTTCCCGGCAACAATTAATAGACTGGATGGAGGCGGATAAAGTTGCAGGACCACTTCTGCGCTCGGCCCTTCCGGCTGGCTGGTTTATTGCTGATAAATCTGGAGCCGGTGAGCGTGGGTCTCGCGGTATCATTGCAGCACTGGGGCCAGATGGTAAGCCCTCCCGTATCGTAGTTATCTACACGACGGGGAGTCAGGCAACTATGGATGAACGAAATAGACAGATCGCTGAGATAGGTGCCTCACTGATTAAGCATTGGTAACTGTCAGACCAAGTTTACTCATATATACTTTAGATTGATTTAAAACTTCATTTTTAATTTAAAAGGATCTAGGTGAAGATCCTTTTTGATAATCTCATGACCAAAATCCCTTAACGTGAGTTTTCGTTCCACTGAGCGTCAGACCCCGTAGAAAAGATCAAAGGATCTTCTTGAGATCCTTTTTTTCTGCGCGTAATCTGCTGCTTGCAAACAAAAAAACCACCGCTACCAGCGGTGGTTTGTTTGCCGGATCAAGAGCTACCAACTCTTTTTCCGAAGGTAACTGGCTTCAGCAGAGCGCAGATACCAAATACTGTCCTTCTAGTGTAGCCGTAGTTAGGCCACCACTTCAAGAACTCTGTAGCACCGCCTACATACCTCGCTCTGCTAATCCTGTTACCAGTGGCTGCTGCCAGTGGCGATAAGTCGTGTCTTACCGGGTTGGACTCAAGACGATAGTTACCGGATAAGGCGCAGCGGTCGGGCTGAACGGGGGGTTCGTGCACACAGCCCAGCTTGGAGCGAACGACCTACACCGAACTGAGATACCTACAGCGTGAGCATTGAGAAAGCGCCACGCTTCCCGAAGGGAGAAAGGCGGACAGGTATCCGGTAAGCGGCAGGGTCGGAACAGGAGAGCGCACGAGGGAGCTTCCAGGGGGAAACGCCTGGTATCTTTATAGTCCTGTCGGGTTTCGCCACCTCTGACTTGAGCGTCGATTTTTGTGATGCTCGTCAGGGGGGCGGAGCCTATGGAAAAACGCCAGCAACGCGGCCTTTTTACGGTTCCTGGCCTTTTGCTGGCCTTTTGCTCACATGTTCTTTCCTGCGTTATCCCCTGATTCTGTGGATAACCGTATTACCGCCTTTGAGTGAGCTGATACCGCTCGCCGCAGCCGAACGACCGAGCGCAGCGAGTCAGTGAGCGAGGAAGCGGAAGAGCGCCCAATACGCAAACCGCCTCTCCCCGCGCGTTGGCCGATTCATTAATGCAGGG

In some embodiments, the nucleic acid is a recombinant adeno-associatedvirus (rAAV) vector. Exemplary rAAV nucleic acid vectors usefulaccording to the disclosure include single-stranded (ss) orself-complementary (sc) AAV nucleic acid vectors.

In some embodiments, a recombinant rAAV particle comprises (or packages)a nucleic acid vector that comprises an expression construct, such as asingle-stranded (ss) or self-complementary (sc) AAV nucleic acid vector.In some embodiments, the nucleic acid vector comprises an expressionconstruct comprising FXN coding sequence (e.g., a human FXN codingsequence) and a truncated FXN 3′ UTR (e.g., a truncated human FXN 3′UTR) operably linked to a promoter (e.g., a Desmin promoter, a CBApromoter, a hFXNPro, or other promoter) and is flanked by regionscomprising inverted terminal repeat (ITR) sequences (e.g., wild-type ITRsequences or engineered ITR sequences). In some embodiments, the nucleicacid is encapsidated by a viral capsid.

Accordingly, in some embodiments, a rAAV particle comprises a viralcapsid and a nucleic acid vector as described herein, which isencapsidated by the viral capsid. In some embodiments, the viral capsidcomprises 60 capsid protein subunits comprising VP1, VP2 and VP3. Insome embodiments, the VP1, VP2, and VP3 subunits are present in thecapsid at a ratio of approximately 1:1:10, respectively.

The ITR sequences of a nucleic acid or nucleic acid vector describedherein can be derived from any AAV serotype (e.g., 1, 2, 3, 4, 5, 6, 7,8, 9.10, 11.12, or 13) or can be derived from more than one serotype. Insome embodiments of the nucleic acid or nucleic acid vector providedherein, the ITR sequences are derived from AAV2. ITR sequences andplasmids containing ITR sequences are known in the art and commerciallyavailable (see, e.g., products and services available from VectorBiolabs. Philadelphia. Pa.; Cellbiolabs, San Diego, Calif.; AgilentTechnologies, Santa Clara. Ca; and Addgene, Cambridge, Mass.; and Genedelivery to skeletal muscle results in sustained expression and systemicdelivery of a therapeutic protein. Kessler P D, Podsakoff G M, Chen X.McQuiston S A, Colosi P C, Matelis L A, Kurtzman G J, Byrne B J. ProcNatl Acad Sci USA. 1996 Nov. 26; 93(24):14082-7; and Curtis A. Machida.Methods in Molecular Medicine^(M). Viral Vectors for Gene TherapyMethods and Protocols. 10.1385/1-59259-304-6:201 © Humana Press Inc.2003. Chapter 10. Targeted Integration by Adeno-Associated Virus.Matthew D. Weitzman, Samuel M. Young Jr., Toni Cathomen and Richard JudeSamulski; U.S. Pat. Nos. 5,139,941 and 5,962,313, all of which areincorporated herein by reference).

In some embodiments, the nucleic acid or nucleic acid vector comprises apTR-UF-11 plasmid backbone, which is a plasmid that contains AAV2 ITRs,or a nucleic acid region of the pTR-UF-11 plasmid that comprises theITRs. This plasmid is commercially available from the American TypeCulture Collection (ATCC MBA-331). One or more genes of interest (forexample encoding a therapeutic protein) under the control of a promoterof interest (for example a Desmin promoter or derivative thereofdescribed in this application) can be inserted in between the ITRs inone these or other plasmids containing AAV ITRs. These can be used asdescribed in this application to produce a rAAV particle encapsidating arAAV nucleic acid comprising ITRs flanking a gene of interest under thecontrol of a promoter of interest.

Genebank reference numbers for sequences of AAV serotypes 1, 2, 3, 3B,4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 are listed in patent publicationWO2012064960, which is incorporated herein by reference in its entirety.

In some embodiments, the expression construct is no more than 7kilobases, no more than 6 kilobases, no more than 5 kilobases, no morethan 4 kilobases, or no more than 3 kilobases in size. In someembodiments, the expression construct is between 4 and 7 kilobases insize.

In some embodiments, the expression construct comprises one or moreregions comprising a sequence that facilitates expression of the FXNcoding sequence, e.g., expression control sequences operably linked tothe FXN coding sequence. Non-limiting examples of expression controlsequences include promoters, insulators, silencers, response elements,introns, enhancers, initiation sites, termination signals, and poly(A)tails. Any combination of such control sequences is contemplated herein(e.g., a promoter and an enhancer). In some embodiments, the promoter isa Desmin promoter as described herein. In some embodiments, theexpression construct contains a splice donor/acceptor site, such asbetween the promoter and the FXN coding sequence.

To achieve appropriate expression levels of FXN, any of a number ofpromoters suitable for use in the selected host cell may be employed.The promoter may be, for example, a constitutive promoter,tissue-specific promoter, inducible promoter, or a synthetic promoter.

For example, constitutive promoters of different strengths can be used.A nucleic acid vector described herein may include one or moreconstitutive promoters, such as viral promoters or promoters frommammalian genes that are generally active in promoting transcription.Non-limiting examples of constitutive viral promoters include the HerpesSimplex virus (HSV), thymidine kinase (TK). Rous Sarcoma Virus (RSV),Simian Virus 40 (SV40). Mouse Mammary Tumor Virus (MMTV), Ad E1A andcytomegalovirus (CMV) promoters. Non-limiting examples of constitutivemammalian promoters include various housekeeping gene promoters, asexemplified by the β-actin promoter (e.g., chicken β-actin promoter) andhuman elongation factor-1α (EF-1α) promoter.

Inducible promoters and/or regulatory elements may also be contemplatedfor achieving appropriate expression levels of FXN. Non-limitingexamples of suitable inducible promoters include those from genes suchas cytochrome P450 genes, heat shock protein genes, metallothioneingenes, and hormone-inducible genes, such as the estrogen gene promoter.Another example of an inducible promoter is the tetVP16 promoter that isresponsive to tetracycline.

Tissue-specific promoters and/or regulatory elements are alsocontemplated herein. Non-limiting examples of such promoters that may beused include hematopoietic stem cell-specific promoters.

Synthetic promoters are also contemplated herein. A synthetic promotermay comprise, for example, regions of known promoters, regulatoryelements, transcription factor binding sites, enhancer elements,repressor elements, and the like.

Although the use of AAV has advanced in recent years, gene transferstill faces some obstacles. For example, tissue specific targeting todeliver the gene to affected organs or to avoid toxicity remains achallenge. High levels of over-expression driven by a strong promotercan lead to toxicity in vitro. In this context, organ specificity ofdifferent promoters can be taken advantage of to achieve sufficient genedelivery to target organs while avoiding complications related toadministration of high doses. In some embodiments, identification of themost efficient and safe promoter element for the transcriptional controlof the FXN transgene can be used to correct FXN deficiency in the heart,CNS and in the pancreatic islet cells. Thus, in some embodiments, thepromoter in the disclosed nucleic acid is a human Desmin promoter or aderivative thereof. The Desmin promoter is a tissue-restricted promoterfor cardiac muscle and neurons. The Desmin promoter element is aderivative of the Desmin gene control element, which contains additionaltranscriptional control elements to augment expression. In someembodiments, the promoter in the disclosed nucleic acid is the chickeni-actin (CBA) promoter. In some embodiments, the CBA promoter is aconstitutive element made up of the cytomegalovirus (CMV) immediateearly enhancer element, the beta-actin promoter and globin intron. Insome embodiments, the CBA promoter allows targeting of muscle, neuronsand the pancreas for FXN transgene delivery. In some embodiments, thepromoter in the disclosed nucleic acid is the endogenous frataxinpromoter (FxP), hFXNPro, which has been mapped to encompass a 1 kbregion 5′ to the frataxin transcriptional start site. In someembodiments, the promoter in the disclosed nucleic acid is theendogenous frataxin promoter (FxP), hFXNPro, which has been mapped toencompass a 1.220 kb region 5′ to the frataxin transcriptional startsite. In some embodiments, no remote enhancer elements are required, andall the necessary transcriptional control and tissue restricted activityare conferred by the frataxin promoter. However, additional regulatorysequences can be used in some embodiments. In some embodiments, the CBApromoter and the hFXNPro allow targeting of the pancreatic islet cellsfor FXN gene delivery. In some embodiments, the nucleic acid is aplasmid (e.g., a circular nucleic acid comprising one or more of anorigin of replication, a selectable marker, and a reporter gene). Insome embodiments, a nucleic acid described herein, such as a plasmid,may also contain marker or reporter genes, e.g., LacZ or a fluorescentprotein, and an origin of replication. In some embodiments, the plasmidis transfected into a producer cell that produces AAV particlescontaining the expression construct (e.g., the expression construct thatwas included in the plasmid that was used to produce the nucleic acidthat was encapsidated by the rAAV particles).

The rAAV particle may be of any AAV serotype (e.g., 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, or 13), including any derivative (includingnon-naturally occurring variants of a serotype) or pseudotype. In someembodiments, the rAAV particle is an AAV9 particle, which may bepseudotyped with AAV2 ITRs. Non-limiting examples of derivatives andpseudotypes include AAV2-AAV3 hybrid, AAVrh.10, AAVhu.14, AAV3a/3b,AAVrh32.33, AAV-HSC15, AAV-HSC17, AAVhu.37, AAVrh.8, CHt-P6, AAV2.5,AAV6.2, AAV2i8, AAV-HSC15/17, AAVM41, AAV9.45, AAV6(Y445F/Y731F).AAV2.5T, AAV-HAE1/2, AAV clone 32/83, AAVShH10, AAV2 (Y->F). AAV8(Y733F), AAV2.15, AAV2.4, AAVM41, and AAVr3.45. Such AAV serotypes andderivatives/pseudotypes, and methods of producing suchderivatives/pseudotypes are known in the art (see, e.g., Mol Ther. 2012April; 20(4):699-708. doi: 10.1038/mt.2011.287. Epub 2012 Jan. 24. TheAAV vector toolkit; poised at the clinical crossroads. Asokan Al,Schaffer D V, Samulski R J.). In some embodiments, the rAAV particle isa pseudotyped rAAV particle, which comprises (a) a nucleic acid vectorcomprising ITRs from one scrotype (e.g., AAV2) and (b) a capsidcomprised of capsid proteins derived from another serotype (e.g., AAV1,AAV3. AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, or AAVIO0). Methods forproducing and using pseudotyped rAAV vectors are known in the art (see,e.g., Duan et al., J. Virol., 75:7662-7671, 2001: Halbert et al., J.Virol., 74:1524-1532, 2000; Zolotukhin et al., Methods, 28:158-167,2002: and Auricchio et al., Hum. Molec. Genet., 10:3075-3081, 2001).

Methods of producing rAAV particles and nucleic acid vectors are alsoknown in the art and commercially available (see. e.g., Zolotukhin etal., Production and purification of serotype 1, 2, and 5 recombinantadeno-associated viral vectors. Methods 28 (2002) 158 167; and U.S.Patent Publication Numbers US20070015238 and US20120322861, which areincorporated herein by reference; and plasmids and kits available fromATCC and Cell Biolabs. Inc.). For example, the nucleic acid vector(e.g., as a plasmid) may be combined with one or more helper plasmids.e.g., that contain a rep gene (e.g., encoding Rep78. Rep68, Rep52 andRep40) and a cap gene (encoding VP1, VP2, and VP3), and transfected intoa producer cell line such that the rAAV particle can be packaged andsubsequently purified.

In some embodiments, the packaging is performed in a helper cell orproducer cell, such as a mammalian cell or an insect cell. Exemplarymammalian cells include, but are not limited to. HEK293 cells, COScells. HeLa cells, BHK cells, or CHO cells (see. e.g., ATCC® CRL-1573™.ATCC® CRL-1651 ™, ATCC® CRL-1650™, ATCC® CCL-2. ATCC® CCL-10™, or ATCC®CCL-61™). Exemplary insect cells include, but are not limited to Sf9cells (see, e.g., ATCC® CRL-1711®). The helper cell may comprises repand/or cap genes that encode the Rep protein and/or Cap proteins for usein a method described herein. In some embodiments, the packaging isperformed in vitro.

In some embodiments, the one or more helper plasmids includes a firsthelper plasmid comprising a rep gene and a cap gene and a second helperplasmid comprising other genes that assist in AAV production, such as aE1a gene, a E1b gene, a E4 gene, a E2a gene, and a VA gene. In someembodiments, the rep gene is a rep gene derived from AAV2 and the capgene is derived from AAV5. Helper plasmids, and methods of making suchplasmids, are known in the art and commercially available (see, e.g.,pDF6, pRep, pDM, pDG, pDPlrs, pDP2rs, pDP3rs, pDP4rs, pDP5rs, pDP6rs,pDG(R484E/R585E), and pDPS.ape plasmids from PlasmidFactory, Bielefeld.Germany: other products and services available from Vector Biolabs.Philadelphia, Pa.; Cellbiolabs, San Diego. Calif.; Agilent Technologies,Santa Clara, Ca; and Addgene, Cambridge, Mass.; pxx6; Grimm et al.(1998). Novel Tools for Production and Purification of RecombinantAdenoassociated Virus Vectors, Human Gene Therapy, Vol. 9, 2745-2760;Kern, A. et al. (2003), Identification of a Heparin-Binding Motif onAdeno-Associated Virus Type 2 Capsids. Journal of Virology, Vol. 77,11072-11081; Grimm et al. (2003), Helper Virus-Free. OpticallyControllable, and Two-Plasmid-Based Production of Adeno-associated VirusVectors of Serotypes 1 to 6, Molecular Therapy, Vol. 7, 839-850;Kroncnbcrg et at (2005). A Conformational Change in the Adcno-AssociatedVirus Type 2 Capsid Leads to the Exposure of Hidden VP1 N Termini,Journal of Virology, Vol. 79, 5296-5303; and Moullier, P. and Snyder. R.O. (2008), International efforts for recombinant adenoassociated viralvector reference standards, Molecular Therapy. Vol. 16, 1185-1188).

An exemplary, non-limiting, rAAV particle production method is describednext. One or more helper plasmids are produced or obtained, whichcomprise rep and cap ORFs for the desired AAV serotype and theadenoviral VA, E2A (DBP), and E4 genes under the transcriptional controlof their native promoters. HEK293 cells (available from ATCC®) aretransfected via CaPO₄-mediated transfection, lipids or polymericmolecules such as Polycthylcniminc (PEI) with the helper plasmid(s) anda plasmid containing a nucleic acid vector described herein.Alternatively, in another example, Sf9-based producer stable cell linesare infected with a single recombinant baculovirus containing thenucleic acid vector. As a further alternative, in another example HEK293or BHK cell lines are infected with a HSV containing the nucleic acidvector and optionally one or more helper HSVs containing rep and capORFs as described herein and the adenoviral VA, E2A (DBP), and E4 genesunder the transcriptional control of their native promoters. The HEK293,BHK, or Sf9 cells are then incubated for at least 60 hours to allow forrAAV particle production. The rAAV particles can then be purified usingany method known the art or described herein, e.g., by iodixanol stepgradient. CsCl gradient, chromatography, or polyethylene glycol (PEG)precipitation.

The disclosure also contemplates host cells that comprise at least oneof the disclosed rAAV particles, expression constructs, or nucleic acidvectors. Such host cells include mammalian host cells, with human hostcells being preferred, and may be either isolated, in cell or tissueculture. In the case of genetically modified animal models (e.g., amouse), the transformed host cells may be comprised within the body of anon-human animal itself.

Compositions

Aspects of the disclosure relate to compositions comprising rAAVparticles or nucleic acids described herein. In some embodiments, rAAVparticles described herein are added to a composition. e.g., apharmaceutical composition.

In some embodiments, the composition comprises a pharmaceuticallyacceptable carrier. The term “carrier” refers to a diluent, adjuvant,excipient, or vehicle with which the rAAV particle is administered. Suchpharmaceutical carriers can be sterile liquids, such as water and oils,including those of petroleum oil such as mineral oil, vegetable oil suchas peanut oil, soybean oil, and sesame oil, animal oil, or oil ofsynthetic origin. Saline solutions and aqueous dextrose and glycerolsolutions can also be employed as liquid carriers. Non-limiting examplesof pharmaceutically acceptable carriers include lactose, dextrose,sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate,alginates, tragacanth, gelatin, calcium silicate, microcrystallinecellulose, polyvinylpyrrolidonc, cellulose, water, saline, syrup,methylcellulose, ethylcellulose, hydroxypropylmethylcellulose,polyacrylic acids, lubricating agents (such as talc, magnesium stearate,and mineral oil), wetting agents, emulsifying agents, suspending agents,preserving agents (such as methyl-, ethyl-, andpropyl-hydroxy-benzoates), and pH adjusting agents (such as inorganicand organic acids and bases). Other examples of carriers includephosphate buffered saline. HEPES-buffered saline, and water forinjection, any of which may be optionally combined with one or more ofcalcium chloride dihydrate, disodium phosphate anhydrous, magnesiumchloride hexahydrate, potassium chloride, potassium dihydrogenphosphate, sodium chloride, or sucrose. Other examples of carriers thatmight be used include saline (e.g., sterilized, pyrogen-free saline),saline buffers (e.g., citrate buffer, phosphate buffer, acetate buffer,and bicarbonate buffer), amino acids, urea, alcohols, ascorbic acid,phospholipids, proteins (for example, serum albumin), EDTA, sodiumchloride, liposomes, mannitol, sorbitol, and glycerol. USP gradecarriers and excipients are particularly useful for delivery of rAAVparticles to human subjects. Such compositions may further optionallycomprise a liposome, a lipid, a lipid complex, a microsphere, amicroparticle, a nanosphere, or a nanoparticle, or may be otherwiseformulated for administration to the cells, tissues, organs, or body ofa subject in need thereof. Methods for making such compositions are wellknown and can be found in, for example, Remington: The Science andPractice of Pharmacy, 22^(nd) edition, Pharmaceutical Press, 2012.

Typically, such compositions may contain at least about 0.1% of thetherapeutic agent (e.g., rAAV particle) or more, although the percentageof the active ingredient(s) may, of course, be varied and mayconveniently be between about 1 or 2% and about 70% or 80% or more ofthe weight or volume of the total formulation. Naturally, the amount oftherapeutic agent(s) (e.g., rAAV particle) in eachtherapeutically-useful composition may be prepared is such a way that asuitable dosage will be obtained in any given unit dose of the compound.Factors such as solubility, bioavailability, biological half-life, routeof administration, product shelf life, as well as other pharmacologicalconsiderations will be contemplated by one skilled in the art ofpreparing such pharmaceutical formulations, and as such, a variety ofdosages and treatment regimens may be desirable.

In some embodiments, a composition described herein may be administeredto a subject in need thereof, such as a subject having Friedreich'sataxia. In some embodiments, a method described herein may compriseadministering a composition comprising rAAV particles as describedherein to a subject in need thereof. In some embodiments, the subject isa human subject. In some embodiments, the subject has or is suspected ofhaving a disease that may be treated with gene therapy, such asFriedreich's ataxia.

Methods

Aspects of the disclosure relate to treatment of Friedreich's ataxia. Insome embodiments, the method comprises administering a therapeuticallyeffective amount of an rAAV particle or a composition as describedherein to a subject having Friedreich's ataxia.

To “treat” a disease as the term is used herein, means to reduce thefrequency or severity of at least one sign or symptom of a disease ordisorder experienced by a subject. The compositions described above orelsewhere herein are typically administered to a subject in an effectiveamount, that is, an amount capable of producing a desirable result. Thedesirable result will depend upon the active agent being administered.For example, an effective amount of rAAV particles may be an amount ofthe particles that are capable of transferring an expression constructto a host organ, tissue, or cell. A therapeutically acceptable amountmay be an amount that is capable of treating a disease, e.g.,Friedreich's ataxia. As is well known in the medical and veterinaryarts, dosage for any one subject depends on many factors, including thesubject's size, body surface area, age, the particular composition to beadministered, the active ingredient(s) in the composition, time androute of administration, general health, and other drugs beingadministered concurrently.

The rAAV particle or nucleic acid vector may be delivered in the form ofa composition, such as a composition comprising the active ingredient,such as a rAAV particle described herein, and a pharmaceuticallyacceptable carrier as described herein. The rAAV particles or nucleicacid vectors may be prepared in a variety of compositions, and may alsobe formulated in appropriate pharmaceutical vehicles for administrationto human or animal subjects.

In some embodiments, the number of rAAV particles administered to asubject may be on the order ranging from 10⁶ to 10¹⁴ particles/ml or 10³to 10¹⁵ particles/ml, or any values therebetween for either range, suchas for example, about 10⁶, 10⁷, 10⁸, 10⁹, 10¹⁰, 10¹¹, 10¹², 10¹³, or10¹⁴ particles/ml. In one embodiment, rAAV particles of higher than 10¹¹particles/ml are be administered. In some embodiments, the number ofrAAV particles administered to a subject may be on the order rangingfrom 10⁶ to 10¹⁴ vector genomes(vgs)/ml or 10³ to 10¹⁵ vgs/ml, or anyvalues therebetween for either range, such as for example, about 10⁶.10⁷, 10⁸ 10⁹, 10¹⁰, 10¹¹, 10 ¹², 10 ¹³, or 10¹⁴ vgs/ml. In oneembodiment, rAAV particles of higher than 10¹³ vgs/ml are beadministered. The rAAV particles can be administered as a single dose,or divided into two or more administrations as may be required toachieve therapy of the particular disease or disorder being treated. Insome embodiments, 0.0001 nil to 10 mls are delivered to a subject. Insome embodiments, the number of rAAV particles administered to a subjectmay be on the order ranging from 10⁶-10¹⁴ vg/kg, or any valuestherebetween, such as for example, about 10⁶, 10⁷, 10⁸, 10⁹, 10¹⁰, 10¹¹,10¹², 10¹³, or 10¹⁴ vgs/mg. In some embodiments, the number of rAAVparticles administered to a subject may be on the order ranging from10¹²-10¹⁴ vgs/kg.

If desired, rAAV particles may be administered in combination with otheragents as well, such as, e.g., proteins or polypeptides or variouspharmaceutically-active agents, including one or more systemic ortopical administrations of therapeutic polypeptides, biologically activefragments, or variants thereof. In fact, there is virtually no limit toother components that may also be included, given that the additionalagents do not cause a significant adverse effect upon contact with thetarget cells or host tissues. The rAAV particles may thus be deliveredalong with various other agents as required in the particular instance.Such compositions may be purified from host cells or other biologicalsources, or alternatively may be chemically synthesized.

In certain circumstances it will be desirable to deliver the rAAVparticles in suitably formulated pharmaceutical compositions disclosedherein either subcutaneously, intraocularly, intravitreally,subretinally, parenterally, intravenously (IV),intracerebro-vcntricularly, intramuscularly, intrathecally (IT),intracistcrnally, orally, intrapcritoncally, by oral or nasalinhalation, or by direct injection to one or more cells, tissues, ororgans by direct injection. In some embodiments, the administration is aroute suitable for systemic delivery, such as by intravenous injection.In some embodiments, “administering” or “administration” means providinga material to a subject in a manner that is pharmacologically useful.

To address the systemic manifestations of FRDA, approaches to transferAAV vectors globally that target both the neurological and cardiacimpairment may be needed. Although IV dosing is an advantageous route totransduce the heart, it does not have high translational feasibility forCNS disorders because of the high dose requirement, high distribution toperipheral tissues and reduced efficiency for CNS transduction(Schuster, D. et al., Front Neuronat., 8:42, 2014). However, intrathecal(IT) dosing of AAV9 (e.g., via lumbar cistern or cisterna magna) is aviable, clinically relevant option for global CNS gene delivery (Gray,S. et al., Gene Ther, 20(4):450-9, 2013; Federici, T. et al., Gene Ther.19(8):852, 2012; Snyder, B. et al., Hum Gene Ther, 22(9):1129, 2011). Amethod of treating subjects with FRDA using a combination of differentroutes of administration (e.g., IV and IT), by transduction of cardiacmuscle, pancreas (e.g., pancreatic islet cells), and CNS (e.g., dorsalroot ganglia, and the cerebellum) is contemplated herein. Thus, in someembodiments, rAAV particles or compositions comprising rAAV particlesthat comprise (or package) FXN transgene are administered viaintravenous (IV) injection. In some embodiments, rAAV particles orcompositions comprising rAAV particles that comprise (or package) FXNtransgene are administered via intrathecal (IT) injection. In someembodiments, rAAV particles or compositions comprising rAAV particlesthat comprise (or package) FXN transgene are administered viaintracistemal injection, so as to deliver the rAAV particles within acistern of the brain. In some embodiments, rAAV particles orcompositions comprising rAAV particles that package FXN transgene areadministered via both an intravenous injection and an intrathecalinjection, or via an intravenous injection and an intracistemalinjection.

In some embodiments, more than two (e.g., three, or four) of the abovedescribed routes of administration are utilized.

In some embodiments, the ratio of rAAV particles administered to thesubject via intravenous injection to rAAV particles administered to thesubject via intrathecal injection is in the range of 10:1 to 1:10 (e.g.,10:1, 8:1, 5:1, 4:1, 2:1, 1:1, 1:2, 1:5, 1:8, 1:10), or 50:1 to 1:50(e.g., 50:1, 40:1, 25:1, 30:1, 10:1, 1:1, 1:10, 1:30, 1:25, 1:40, 1:50),or 100:1 to 1:100 (e.g., 100:1, 80:1, 50:1, 10:1, 1:1, 1:10, 1:50, 1:80,1:100), or 1000:1 to 1:1000 (e.g., 1000:1, 800:1, 500:1, 100:1, 1:1,1:100, 1:500, 1:800, 1:1000). In some embodiments, the ratio of rAAVparticles administered to the subject via intravenous injection to rAAVparticles administered to the subject via intracisternal injection is inthe range of 10:1 to 1:10 (e.g., 10:1, 8:1, 5:1, 4:1, 2:1, 1:1, 1:2,1:5, 1:8, 1:10), or 50:1 to 1:50 (e.g., 50:1, 40:1, 25:1, 30:1, 10:1,1:1, 1:10, 1:30, 1:25, 1:40, 1:50), or 100:1 to 1:100 (e.g., 100:1,80:1, 50:1, 10:1, 1:1, 1:10, 1:50, 1:80, 1:100), or 1000:1 to 1:1000(e.g., 1000:1, 800:1, 500:1, 100:1, 1:1, 1:100, 1:500, 1:800, 1:1000).In some embodiments, the ratio of rAAV particles administered to thesubject via intravenous injection to rAAV particles administered to thesubject via intrathecal injection is 1:10. In some embodiments, theratio of rAAV particles administered to the subject via intravenousinjection to rAAV particles administered to the subject viaintracisternal injection is 1:10. In some embodiments, compositionsadministered via intravenous, intrathecal, and/or intracisternalinjection may have the same number of particles or viral genomes perunit volume. However, in some embodiments compositions having differenttiters may be used for different routes of administration. Also,different compositions having different components in addition to theviral particles may be used for different routes of administration.

The amount of rAAV particle or nucleic acid vector compositions and timeof administration of such compositions will be within the purview of theskilled artisan having benefit of the present teachings. It is likely,however, that the administration of therapeutically-effective amounts ofthe disclosed compositions may be achieved by a single administration,such as for example, a single injection of sufficient numbers ofinfectious particles to provide therapeutic benefit to the patientundergoing such treatment. Alternatively, in some circumstances, it maybe desirable to provide multiple, or successive administrations of therAAV particle compositions, either over a relatively short, or arelatively prolonged period of time, as may be determined by the medicalpractitioner overseeing the administration of such compositions.

In some embodiments, when more than one route of administration isutilized, the administration of rAAV comprising FXN transgene via thetwo or more routes is performed simultaneously, or within 10 min of eachother. In some embodiments, when more than one route of administrationis utilized, the administration of rAAV comprising FXN transgene via thetwo or more mutes is staggered, so that administration via the secondroute is performed 10 min, 20 min. 30 min 1 h, 2 h, 3 h, 4 h, 5 h, 6 h,8 h, 12 h, 18 h, or 24 h after the administration via the first route.In some embodiments, when more than one route of administration isutilized, the administration of rAAV comprising FXN transgene via thetwo or more routes is altered, so that administration via the secondroute replaces administration via the first route on a routine basis(e.g., for once a day schedule, administration via first route on day 1,administration via second route on day 2, administration via first routeon day 3, administration via second route on day 4, and so on).

In some embodiments, the number of rAAV particles administered to asubject may be on the order ranging from 10⁶ to 10¹⁴ particles/mL or 10³to 10¹³ particles/mL, or any values therebetween for either range, suchas for example, about 10⁶. 10⁷. 10⁸, 10⁹, 10¹⁰, 10¹¹, 10 ¹², 10¹³, or10¹⁴ particles/mL. In some embodiments, rAAV particle compositions oflower than 10⁷ particles/mL, for example lower than 10³ particles/mL,are administered. In some embodiments, rAAV particle compositions ofhigher than 10¹³ particles/mL, for example higher than 10¹⁵particles/mL, are administered. In some embodiments, the number of rAAVparticles administered to a subject may be on the order ranging from 10⁶to 10¹⁴ vector genomes(vgs)/mL or 10³ to 10¹⁵ vgs/mL, or any valuesthere between for either range, such as for example, about 10⁶, 10⁷,10⁸, 10⁹, 10¹⁰, 10¹¹, 10¹², 10¹³, or 10¹⁴ vgs/mL. In some embodiments,rAAV particle compositions of lower than 10′ vgs/mL, for example lowerthan 10³ vgs/mL, are be administered. In some embodiments, rAAV particlecompositions of higher than 10¹³ vgs/mL, for example higher than 10¹⁵vgs/mL, are administered. In some embodiments, 0.0001 mL to 10 mLs aredelivered to a subject (e.g., via one or more routes of administrationas described in this application).

IV and IT injections are routine non-surgical procedures that are oftendone in an outpatient setting with minimal risk (Mattar. C. et al.,FASEB J. 29(9):3876, 2015; Gray, S. et al. Gene Ther. 20(4):450-9, 2013:Federici. T. et al., Gene Ther. 19(8):852, 2012; Snyder, B. et al., HumGene Ther, 22(9):1129, 2011).

The pharmaceutical forms of the rAAV particle compositions suitable forinjectable use include sterile aqueous solutions or dispersions. In someembodiments, the form is sterile and fluid to the extent that easysyringability exists. In some embodiments, the form is stable under theconditions of manufacture and storage and is preserved against thecontaminating action of microorganisms, such as bacteria and fungi. Insome embodiments, the form is sterile. The carrier can be a solvent ordispersion medium containing, for example, water, saline, ethanol,polyol (e.g., glycerol, propylene glycol, and liquid polyethyleneglycol, and the like), suitable mixtures thereof, and/or vegetable oils.Proper fluidity may be maintained, for example, by the use of a coating,such as lecithin, by the maintenance of the required particle size inthe case of dispersion and by the use of surfactants.

For administration of an injectable aqueous solution, for example, thesolution may be suitably buffered, if necessary, and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous,intramuscular, intravitreal, subretinal, subcutaneous andintraperitoneal administration. In this connection, a sterile aqueousmedium that can be employed will be known to those of skill in the artin light of the present disclosure. For example, one dosage may bedissolved in 1 ml of isotonic NaCl solution and either added to 1000 mlof hypodermoclysis fluid or injected at the proposed site of infusion,(see for example, “Remington's Pharmaceutical Sciences” 15th Edition,pages 1035-1038 and 1570-1580). Some variation in dosage willnecessarily occur depending on the condition of the subject beingtreated. The person responsible for administration will, in any event,determine the appropriate dose for the individual subject. Moreover, forhuman administration, preparations should meet sterility, pyrogenicity,and the general safety and purity standards as required by, e.g., FDAOffice of Biologics standards.

Sterile injectable solutions are prepared by incorporating the rAAVparticles in the required amount in the appropriate solvent with severalof the other ingredients enumerated above, as required, followed byfiltered sterilization or another sterilization technique. Generally,dispersions are prepared by incorporating the various sterilized activeingredients into a sterile vehicle which contains the basic dispersionmedium and the required other ingredients from those enumerated above.In the case of sterile powders for the preparation of sterile injectablesolutions, the preferred methods of preparation are vacuum-drying andfreeze-drying techniques which yield a powder of the active ingredientplus any additional desired ingredient from a previouslysterile-filtered solution thereof.

The composition may include rAAV particles, either alone, or incombination with one or more additional active ingredients, which may beobtained from natural or recombinant sources or chemically synthesized.

Toxicity and efficacy of the compositions utilized in methods of thedisclosure can be determined by standard pharmaceutical procedures,using either cells in culture or experimental animals to determine theLD50 (the dose lethal to 50% of the population). The dose ratio betweentoxicity and efficacy the therapeutic index and it can be expressed asthe ratio LD50/ED50. Those compositions that exhibit large therapeuticindices are preferred. While those that exhibit toxic side effects maybe used, care should be taken to design a delivery system that minimizesthe potential damage of such side effects. The dosage of compositions asdescribed herein lies generally within a range that includes an ED50with little or no toxicity. The dosage may vary within this rangedepending upon the dosage form employed and the route of administrationutilized.

Subjects

Aspects of the disclosure relate to methods for use with a subject, suchas human or non-human primate subjects. Non-limiting examples ofnon-human primate subjects include macaques (e.g., cynomolgus or rhesusmacaques), marmosets, tamarins, spider monkeys, owl monkeys, vervetmonkeys, squirrel monkeys, baboons, gorillas, chimpanzees, andorangutans. In some embodiments, the subject is a human subject. Otherexemplary subjects include domesticated animals such as dogs and cats;livestock such as horses, cattle, pigs, sheep, goats, and chickens; andother animals such as mice, rats, guinea pigs, and hamsters.

In some embodiments, the subject has or is suspected of having a diseasethat may be treated with gene therapy. In some embodiments, the subjecthas or is suspected of having Friedreich's ataxia. Friedreich's ataxia(FRDA) is a rare inherited disease that causes degeneration of thespinal cord and peripheral nervous system. Subjects with FRDA generallyhave an expanded number of GAA repeats in the FXN gene. A subjectgenerally must have both copies of the FXN with expanded repeats todevelop FRDA, although about 2 percent of subjects have one copy of theFXN gene with expanded repeats and another different type of mutation inthe other copy of the FXN gene. Generally, if a subject has more than 66to more than 1.000 GAA repeats in both copies of the FXN gene, they willdevelop FRDA. Symptoms of FRDA include gait ataxia, loss of sensation inthe extremities, loss of tendon reflexes, scoliosis, dysarthria, hearingloss, vision loss, chest pain, shortness of breath, and heartpalpitations. Subjects with FRDA may also develop carbohydrateintolerance or diabetes. Subjects with fewer than 300 repeats maydevelop symptoms later in life than those with additional repeats.Subject having FRDA can be identified by the skilled practitioner usingmethods known in the art or described herein. e.g., using genetictesting, electromyogram (EMG), nerve conduction studies,electrocardiogram (ECG), echocardiogram, blood tests for elevatedglucose and vitamin E, magnetic resonance imaging (MRI) or computedtomography (CT) scans, and combinations thereof.

Without further elaboration, it is believed that one skilled in the artcan, based on the above description, utilize the present disclosure toits fullest extent. The following specific embodiments are, therefore,to be construed as merely illustrative, and not limitative of theremainder of the disclosure in any way whatsoever. All publicationscited herein are incorporated by reference for the purposes or subjectmatter referenced herein.

EXAMPLES Example 1: Frataxin: A Putative Biomarker for Minimal EffectiveDosage of AAV Gene Therapy

Fricdrich ataxia (FRDA) is an autosomal recessive ncurodcgencrativedisorder caused by a triplet repeat expansion in the frataxin gene(FXN), which encodes the mitochondrial protein frataxin. Deficiency infrataxin expression results in severe mitochondrial dysfunction leadingto progressive gait abnormality, impaired muscle coordination, muscleweakness, hyporeflexia, dysmetria, dysarthria, and hypertrophiccardiomyopathy. Currently, there are no approved treatments for FRDA,which is the most common occurring autosomal recessive ataxia, affecting1 in 50,000 people worldwide. Precise quantification of frataxin levelsis critical for establishing the effectiveness of potential therapies.Therefore, methods that improve detection of FXN expression willfacilitate the implementation of novel therapies into a clinicalsetting. The overall objective was to establish an approach foreffective gene transfer and quantification of frataxin levels sufficientto restore mitochondrial function. Stable isotope labeling of aminoacids in cell culture or in mammals (SILAC/M) is a novel and sensitivemass spectrometry based approach used herein for the quantification offrataxin levels; therefore enabling determination of required levels forcorrection of FXN deficiency.

A rAAV2/9-FXN vector expressing codon optimized human FXN was generatedfor use in models of FRDA, rAAV2/9 means that the nucleic acid vectorcontained AAV2 ITRs and the capsid encapsidating the nucleic acid vectorwas an AAV9 capsid. A map of a non-limiting plasmid containing the FXNexpression construct is shown in FIG. 1. The sequence of the plasmid isbelow. The sequence of the Desmin promoter in the plasmid is also shown(SEQ ID NO: 2, and see also FIG. 6). The frataxin gene sequence wascodon-optimized using LifeTechnologies strategy using GeneOptimizer®software which calculates the optimal DNA sequence needed to encode theprotein of interest (gene optimization).

AAV plasmid with Human FXN codon-optimized coding sequence and truncated3′ UTR driven by Desmin promoter (ITR from position 22-164, Desminpromoter from position 171-882, SD/SA from position 896-1026, CDS (codonoptimized human Frataxin—hFXNco) from position 1087-2034, 3′ UTR (humanFXN 3′ UTR) from position 2035-3525, polyA signal from position3550-3771, and ITR (complement) from position 3792-3934):

(SEQ ID NO: 10)   1 CTGCAGGGGG GGGGGGGGGG GGGTTGGCCA CTCCCTCTCT GCGCGCTCGC TCGCTCACTG  61 AGGCCGGGCG ACCAAAGGTC GCCCGACGCC CGGGCTTTGC CCGGGCGGCC TCAGTGAGCG 121 AGCGAGCGCG CAGAGAGGGA GTGGCCAACT CCATCACTAG GGGTTCCTCA GATCTTACCC 181 CCTGCCCCCC ACAGCTCCTC TCCTGTGCCT TGTTTCCCAG CCATGCGTTC TCCTCTATAA 241 ATACCCGCTC TGGTATTTGG GGTTGGCAGC TGTTGCTGCC AGGGAGATGG TTGGGTTGAC 301 ATGCGGCTCC TGACAAAACA CAAACCCCTG GTGTGTGTGG GCGTGGGTGG TGTGAGTAGG 361 GGGATGAATC AGGGAGGGGG CGGGGGACCC AGGGGGCAGG AGCCACACAA AGTCTGTGCG 421 GGGGTGGGAG CGCACATAGC AATTGGAAAC TGAAAGCTTA TCAGACCCTT TCTGGAAATC 481 AGCCCACTGT TTATAAACTT GAGGCCCCAC CCTCGAGATA ACCAGGGCTG AAAGAGGCCC 541 GCCTGGGGGC TGGAGACATG CTTGCTGCCT GCCCTGGCGA AGGATTGGCA GGCTTGCCCG 601 TCACAGGACC CCCGCTGGCT GACTCAGGGG CGCAGGCCTC TTGCGGGGGA GCTGGCCTCC 661 CCGCCCCCAC GGCCACGGGC CGCCCTTTCC TGGCAGGACA GCGGGATCTT GCAGCTGTCA 721 GGGGAGGGGA GGCGGGGGCT GATGTCAGGA GGGATACAAA TAGTGCCGAC GGCTGGGGGC 781 CCTGTCTCCC CTCGCCGCAT CCACTCTCCG GCCGGCCGCC TGTCCGCCGC CTCCTCCGTG 841 CGCCCGCCAG CCTCGCCCGC GCCGTCACCG TGAGGCACTG GGCAGGTAAG TATCAAAGTA 901 TCAAGGTTAC AAGACAGGTT TAAGGAGACC AATAGAAACT GGGCTTGTCG AGACAGAGAA 961 GACTCTTGCG TTTCTGATAG GCACCTATTG GTCTTACTGA CATCCACTTT GCCTTTCTCT1021 CCACAGGCTA GCCTCGAGAA TTCACGCGTG GTACCTCTAG AGTCGACCGA TATCACTAGT1081 GCCACCATCT GGACACTGGG GAGAAGGGCC GTGGCTGGAC TGCTGGCTTC TCCATCTCCA1141 GCCCAGGCCC AGACCCTGAC CAGAGTGCCT AGACCTGCCG AACTGGCCCC TCTGTGTGGC1201 AGAAGAGGCC TGAGAACCGA CATCGACGCC ACCTGTACCC CCAGAAGGGC CAGCAGCAAT1261 CAGCGGGGCC TGAATCAGAT CTGGAACGTG AAGAAACAGA GCGTGTACCT GATGAACCTG1321 AGAAAGAGCG GCACCCTGGG CCACCCTGGA AGCCTGGATG AGACAACCTA CGAGCGGCTG1381 GCCGAGGAAA CCCTGGATTC CCTGGCCGAG TTCTTCGAGG ACCTGGCCGA CAAGCCCTAC1441 ACCTTCGAGG ATTACGACGT GTCCTTCGGC AGCGGCGTGC TGACAGTGAA GCTGGGCGGA1501 GATCTGGGCA CCTACGTGAT CAACAAGCAG ACCCCCAACA AACAGATCTG GCTGAGCAGC1561 CCCAGCAGCG GCCCCAAGAG ATACGATTGG ACCGGCAAGA ACTGGGTGTT CAGCCACGAC1621 GGCGTGTCCC TGCATGAGCT GCTGGCTGCC GAGCTGACCA AGGCCCTGAA AACAAAGCTG1681 GACCTGAGCT GGCTGGCCTA CAGCGGCAAA GATGCCATCG ATATCCCCAG CCCCGTTTTA1741 AGGACATTAA AAGCTATCAG GCCAAGACCC CAGCTTCATT ATGCAGCTGA GGTCTGTTTT1801 TTGTTGTTGT TGTTGTTTAT TTTTTTTATT CCTGCTTTTG AGGACAGTTG GGCTATGTGT1861 CACAGCTCTG TAGAAAGAAT GTGTTGCCTC CTACCTTGCC CCCAAGTTCT GATTTTTAAT1921 TTCTATGGAA GATTTTTTGG ATTGTCGGAT TTCCTCCCTC ACATGATACC CCTTATCTTT1981 TATAATGTCT TATGCCTATA CCTGAATATA ACAACCTTTA AAAAAGCAAA ATAATAAGAA2041 GGAAAAATTC CAGGAGGGAA AATGAATTGT CTTCACTCTT CATTCTTTGA AGGATTTACT2101 GCAAGAAGTA CATGAAGAGC AGCTGGTCAA CCTGCTCACT GTTCTATCTC CAAATGAGAC2161 ACATTAAAGG GTAGCCTACA AATGTTTTCA GGCTTCTTTC AAAGTGTAAG CACTTCTGAG2221 CTCTTTAGCA TTGAAGTGTC GAAAGCAACT CACACGGGAA GATCATTTCT TATTTGTGCT2281 CTGTGACTGC CAAGGTGTGG CCTGCACTGG GTTGTCCAGG GAGACATGCA TCTAGTGCTG2341 TTTCTCCCAC ATATTCACAT ACGTGTCTGT GTGTATATAT ATTTTTTCAA TTTAAAGGTT2401 AGTATGGAAT CAGCTGCTAC AAGAATGCAA AAAATCTTCC AAAGACAAGA AAAGAGGAAA2461 AAAAGCCGTT TTCATGAGCT GAGTGATGTA GCGTAACAAA CAAAATCATG GAGCTGAGGA2521 GGTGCCTTGT AAACATGAAG GGGCAGATAA AGGAAGGAGA TACTCATGTT GATAAAGAGA2581 GCCCTGGTCC TAGACATAGT TCAGCCACAA AGTAGTTGTC CCTTTGTGGA CAAGTTTCCC2641 AAATTCCCTG GACCTCTGCT TCCCCATCTG TTAAATGAGA GAATAGAGTA TGGTTGATTC2701 CCAGCATTCA GTGGTCCTGT CAAGCAACCT AACAGGCTAG TTCTAATTCC CTATTGGGTA2761 GATGAGGGGA TGACAAAGAA CAGTTTTTAA GCTATATAGG AAACATTGTT ATTGGTGTTG2821 CCCTATCGTG ATTTCAGTTG AATTCATGTG AAAATAATAG CCATCCTTGG CCTGGCGCGG2881 TGGCTCACAC CTGTAATCCC AGCACTTTTG GAGGCCAAGG TGGGTGGATC ACCTGAGGTC2941 AGGAGTTCAA GACCAGCCTG GCCAACATGA TGAAACCCCG TCTCTACTAA AAATACAAAA3001 AATTAGCCGG GCATGATGGC AGGTGCCTGT AATCCCAGCT ACTTGGGAGG CTGAAGCGGA3061 AGAATCGCTT GAACCCAGAG GTGGAGGTTG CAGTGAGCCG AGATCGTGCC ATTGCACTGT3121 AACCTGGGTG ACTGAGCAAA ACTCTGTCTC AAAATAATAA TAACAATATA ATAATAATAA3181 TAGCCATCCT TTATTGTACC CTTACTGGGT TAATCGTATT ATACCACATT ACCTCATTTT3241 AATTTTTACT GACCTGCACT TTATACAAAG CAACAAGCCT CCAGGACATT AAAATTCATG3301 CAAAGTTATG CTCATGTTAT ATTATTTTCT TACTTAAAGA AGGATTTATT AGTGGCTGGG3361 CATGGTGGCG TGCACCTGTA ATCCCAGGTA CTCAGGAGGC TGAGACGGGA GAATTGCTTG3421 ACCCCAGGCG GAGGAGGTTA CAGTGAGTCG AGATCGTACC TGAGCGACAG AGCGAGACTC3481 CGTCTCAAAA AAAAAAAAAA GGAGGGTTTA TTAATGAGAA GTTTGGTCGA CTAGAGCGGC3541 CCCTTCGAGC AGACATGATA AGATACATTG ATGAGTTTGG ACAAACCACA ACTAGAATGC3601 AGTGAAAAAA ATGCTTTATT TGTGAAATTT GTGATGCTAT TGCTTTATTT GTAACCATTA3661 TAAGCTGCAA TAAACAAGTT AACAACAACA ATTGCATTCA TTTTATGTTT CAGGTTCAGG3721 GGGAGATGTG GGAGGTTTTT TAAAGCAAGT AAAACCTCTA CAAATGTGGT AAAATCGATA3781 AGGATCTAGG AACCCCTAGT GATGGAGTTG GCCACTCCCT CTCTGCGCGC TCGCTCGCTC3841 ACTGAGGCCG CCCGGGCAAA GCCCGGGCGT CGGGCGACCT TTGGTCGCCC GGCCTCAGTG3901 AGCGAGCGAG CGCGCAGAGA GGGAGTGGCC AACCCCCCCC CCCCCCCCCC TGCAGCCTGG3961 CGTAATAGCG AAGAGGCCCG CACCGATCGC CCTTCCCAAC AGTTGCGTAG CCTGAATGGC4021 GAATGGCGCG ACGCGCCCTG TAGCGGCGCA TTAAGCGCGG CGGGTGTGGT GGTTACGCGC4081 AGCGTGACCG CTACACTTGC CAGCGCCCTA GCGCCCGCTC CTTTCGCTTT CTTCCCTTCC4141 TTTCTCGCGA CGTTCGCCGG CTTTCCCCGT CAAGCTCTAA ATCGGGGGCT CCCTTTAGGG4201 TTCCGATTTA GTGCTTTACG GCACCTCGAC CCCAAAAAAC TTGATTAGGG TGATGGTTCA4261 CGTAGTGGGC CATCGCCCTG ATAGACGGTT TTTCGCCCTT TGACGTTGGA GTCCACGTTC4321 TTTAATAGTG GACTCTTGTT CCAAACTGGA ACAACACTCA ACCCTATCTC GGTCTATTCT4381 TTTGATTTAT AAGGGATTTT GCCGATTTCG GCCTATTGGT TAAAAAATGA GCTGATTTAA4441 CAAAAATTTA ACGCGAATTT TAACAAAATA TTAACGTTTA CAATTTCCTG ATGCGGTATT4501 TTCTCCTTAC GCATCTGTGC GGTATTTCAC ACCGCATATG GTGCACTCTC AGTACAATCT4561 GCTCTGATGC CGCATAGTTA AGCCAGCCCC GACACCCGCC AACACCCGCT GACGCGCCCT4621 GACGGGCTTG TCTGCTCCCG GCATCCGCTT ACAGACAAGC TGTGACCGTC TCCGGGAGCT4681 GCATGTGTCA GAGGTTTTCA CCGTCATCAC CGAAACGCGC GAGACGAAAG GGCCTCGTGA4741 TACGCCTATT TTTATAGGTT AATGTCATGA TAATAATGGT TTCTTAGACG TCAGGTGGCA4801 CTTTTCGGGG AAATGTGCGC GGAACCCCTA TTTGTTTATT TTTCTAAATA CATTCAAATA4861 TGTATCCGCT CATGAGACAA TAACCCTGAT AAATGCTTCA ATAATATTGA AAAAGGAAGA4921 GTATGAGTAT TCAACATTTC CGTGTCGCCC TTATTCCCTT TTTTGCGGCA TTTTGCCTTC4981 CTGTTTTTGC TCACCCAGAA ACGCTGGTGA AAGTAAAAGA TGCTGAAGAT CAGTTGGGTG5041 CACGAGTGGG TTACATCGAA CTGGATCTCA ACAGCGGTAA GATCCTTGAG AGTTTTCGCC5101 CCGAAGAACG TTTTCCAATG ATGAGCACTT TTAAAGTTCT GCTATGTGGC GCGGTATTAT5161 CCCGTATTGA CGCCGGGCAA GAGCAACTCG GTCGCCGCAT ACACTATTCT CAGAATGACT5221 TGGTTGAGTA CTCACCAGTC ACAGAAAAGC ATCTTACGGA TGGCATGACA GTAAGAGAAT5281 TATGCAGTGC TGCCATAACC ATGAGTGATA ACACTGCGGC CAACTTACTT CTGACAACGA5341 TCGGAGGACC GAAGGAGCTA ACCGCTTTTT TGCACAACAT GGGGGATCAT GTAACTCGCC5401 TTGATCGTTG GGAACCGGAG CTGAATGAAG CCATACCAAA CGACGAGCGT GACACCACGA5461 TGCCTGTAGC AATGGCAACA ACGTTGCGCA AACTATTAAC TGGCGAACTA CTTACTCTAG5521 CTTCCCGGCA ACAATTAATA GACTGGATGG AGGCGGATAA AGTTGCAGGA CCACTTCTGC5581 GCTCGGCCCT TCCGGCTGGC TGGTTTATTG CTGATAAATC TGGAGCCGGT GAGCGTGGGT5641 CTCGCGGTAT CATTGCAGCA CTGGGGCCAG ATGGTAAGCC CTCCCGTATC GTAGTTATCT5701 ACACGACGGG GAGTCACCCA ACTATGGATG AACCAAATAG ACAGATCGGT GAGATAGGTG5761 CCTCACTGAT TAAGCATTGG TAACTGTCAG ACCAAGTTTA CTCATATATA CTTTAGATTG5821 ATTTAAAACT TCATTTTTAA TTTAAAAGGA TCTAGGTGAA GATCCTTTTT GATAATCTCA5881 TGACCAAAAT CCCTTAACGT GAGTTTTCGT TCCACTGAGC GTCAGACCCC GTAGAAAAGA5941 TCAAAGGATC TTCTTGAGAT CCTTTTTTTC TGCGCGTAAT CTGCTGCTTG CAAACAAAAA6001 AACCACCGCT ACCAGCGGTG GTTTGTTTGC CGGATCAAGA GCTACCAACT CTTTTTCCGA6061 AGGTAACTGG CTTCAGCAGA GCGCAGATAC CAAATACTGT CCTTCTAGTG TAGCCGTAGT6121 TAGGCCACCA CTTCAAGAAC TCTGTAGCAC CGCCTACATA CCTCGCTCTG CTAATCCTGT6181 TACCAGTGGC TGCTGCCAGT GGCGATAAGT CGTGTCTTAC CGGGTTGGAC TCAAGACGAT6241 AGTTACCGGA TAAGGCGCAG CGGTCGGGCT GAACGGGGGG TTCGTGCACA CAGCCCAGCT6301 TGGAGCGAAC GACCTACACC GAACTGAGAT ACCTACAGGG TGAGCATTGA GAAAGCGCCA6361 CGCTTCCCGA AGGGAGAAAG GCGGACAGGT ATCCGGTAAG CGGCAGGGTC GGAACAGGAG6421 AGCGCACGAG GGAGCTTCCA GGGGGAAACG CCTGGTATCT TTATAGTCCT GTCGGGTTTC6481 GCCACCTCTG ACTTGAGCGT CGATTTTTGT GATGCTCGTC AGGGGGGCGG AGCCTATGGA6541 AAAACGCCAG CAACGCGGCC TTTTTACGGT TCCTGGCCTT TTGCTGGCCT TTTGCTCACA6601 TGTTCTTTCC TGCGTTATCC CCTGATTCTG TGGATAACCG TATTACCGCC TTTGAGTGAG6661 CTGATACCGC TCGCCGCAGC CGAACGACCG AGCGCAGCGA GTCAGTGAGC GAGGAAGCGG6721 AAGAGCGCCC AATACGCAAA CCGCCTCTCC CCGCGCGTTG GCCGATTCAT TAATGCAGGG

A polypeptidc translation is as follows:

(SEQ ID NO: 11) MWTLGRRAVAGLLASPSPAQAQTLTRVPRPAELAPLCGRRGLRTDIDATCTPRRASSNQRGLNQIWNVKKQSVYLMNLRKSGTLGHPGSLDETTYERLAEETLDSLAEFFEDLADKPYTFEDYDVSFGSGVLTVKLGGDLGTYVINKQTPNKQIWLSSPSSGPKRYDWTGKNWVFSHDGVSLHELLAAELTKALKTKLDLSWLAYSGKDAIDIPSPVLRTLKAIRPRPQLHYAAEVCFLLLLLFIFFIPAFEDSWAMCHSSVERMCCLLPCPQVLIFNFYGRFFGLSDFLPHMIPLIFYNVLCLYLNITTFKKAK

Renal epithelial cells (REC) were isolated from control and FRDApatients, and SILAC was used to quantify AAV-mediated FXN expressionin-vitro. Induced pluripotent stem cells (IPSC) were generated from theRECs. and were subsequently differentiated to cardiomyocytes andneurons. AAV-mediated correction of FXN was verified by increasedmitochondrial activity including reduced iron deposition and increasedaconitase function in FRDA cells. Preliminary results showed thatSILAC/M was able to accurately measure endogenous and vector derived FXNexpression in-vitro and in-vivo. Moreover, improvement in mitochondrialfunction was correlated with levels of FXN expression in vitro. Thesestudies indicate that rAAV vectors of the present disclosure are usefulto treat FRDA.

Example 2: Development of an AAV Vector to Treat Friedreich's Ataxia

A clinical candidate vector was designed to express frataxin. The vectorcontained an expression cassette with human Desmin (DES) promoterdriving codon-optimized human FXN with a truncated human FXN 3′ UTR. Theexpression cassette was flanked by AAV2 ITRs. The plasmid containing theexpression cassette is shown in FIG. 1 and is further described inExample 1. The plasmid was used with AAV2 rep and AAV9 capsid helperplasmids to package the vector in an AAV9 capsid, resulting inrAAV2/9-FXN, which was used in all of the studies described below.

A cellular model of FRDA was developed as follows. FA2 cells are renalepithelial cells that were derived from FRDA patients (FIG. 2A). Inducedpluripotent stem cells (IPSCs) were generated from the FA2 cells (FIG.2B) and were differentiated into cardiomyocytes (FIG. 2C) and neuralprogenitor cells. Cardiomyocyte differentiation took about two weeks,whereas neural progenitor cell differentiation took about three weeks.

The IPSC differentiation to cardiomyocytes and progenitor cells wasvalidated by assessing cardiac and neuronal markers. NKX2.5 andTroponinT were used as markers of cardiomyocytes. The IPSCsdifferentiated into cardiomyocytes expressed both markers (FIG. 3A).Neurofluor CDr3 was used to confirm neural progenitor celldifferentiation. The IPSCs differentiated into neural progenitorsstained positive with Neurofluor CDr3 (FIG. 3B).

Next, FA2 cells were transiently transfected with the plasmid containingthe FXN expression construct and FXN protein levels were analyzed byWestern Blot and the Li—COR Odyssey Imaging system. FA2 transientlytransfected cells showing dose dependent increases of FXN (FIG. 4).

Lastly, an aconitase activity assay was used to assess mitochondrialhealth in FA2 cells. Aconitase is a robust indicator of mitochondrialhealth. Moreover, in FXN deficient environments aconitase becomessusceptible to ROS attack. FA2 cells were transiently transfected withthe plasmid containing the FXN expression construct. Aconitase activitywas higher in FA2 cells transfected with the plasmid than in FA2 cellsnot transfected with the plasmid (FIGS. 5A and 5B).

These results show that correction of FXN expression in-vitro increasedaconitase activity. Aconitase activity increased proportionally to FXNin a dose dependent manner. Western Blot analysis revealed that theexpression vector generated transcriptionally and functionally activeFXN. These results suggest that rAAV compositions of the presentdisclosure are useful, in some embodiments, for AAV-mediated genetherapy for FXN replacement in Friedreich's Ataxia.

OTHER EMBODIMENTS

All of the features disclosed in this specification may be combined inany combination. Each feature disclosed in this specification may bereplaced by an alternative feature serving the same, equivalent, orsimilar purpose. Thus, unless expressly stated otherwise, each featuredisclosed is only an example of a generic series of equivalent orsimilar features.

From the above description, one skilled in the art can easily ascertainthe essential characteristics of the present disclosure, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the disclosure to adapt it to various usages andconditions. Thus, other embodiments are also within the claims.

EQUIVALENTS

While several inventive embodiments have been described and illustratedherein, those of ordinary skill in the art will readily envision avariety of other means and/or structures for performing the functionand/or obtaining the results and/or one or more of the advantagesdescribed herein, and each of such variations and/or modifications isdeemed to be within the scope of the inventive embodiments describedherein. More generally, those skilled in the art will readily appreciatethat all parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the inventive teachingsis/are used. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, many equivalentsto the specific inventive embodiments described herein. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, inventive embodiments may be practicedotherwise than as specifically described and claimed. Inventiveembodiments of the present disclosure are directed to each individualfeature, system, article, material, kit, and/or method described herein.In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

All references, patents and patent applications disclosed herein areincorporated by reference with respect to the subject matter for whicheach is cited, which in some cases may encompass the entirety of thedocument.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one cmbodimcnt to A only (optionally including elcmcnts other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of.” or, when usedin the claims. “consisting of,” will refer to the inclusion of exactlyone element of a number or list of clcmcnts. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e., “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example. “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one. A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including.” “carrying,” “having.”“containing.” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03. It should be appreciatedthat embodiments described in this document using an open-endedtransitional phrase (e.g., “comprising”) are also contemplated, inalternative embodiments, as “consisting of” and “consisting essentiallyof” the feature described by the open-ended transitional phrase. Forexample, if the disclosure describes “a composition comprising A and B”,the disclosure also contemplates the alternative embodiments “acomposition consisting of A and B” and “a composition consistingessentially of A and B”.

What is claimed is:
 1. A nucleic acid comprising an expression constructcomprising a human frataxin (FXN) coding sequence and a truncated humanFXN 3′ untranslated region (UTR) operably linked to a promoter, whereinthe expression construct is flanked on each side by an inverted terminalrepeat sequence.
 2. The nucleic acid of claim 1, wherein the human FXNcoding sequence is codon-optimized for expression in human cells.
 3. Thenucleic acid of claim 2, wherein the FXN coding sequence comprises thesequence of SEQ ID NO:
 1. 4. The nucleic acid of any one of claims 1 to3, wherein the promoter comprises one or more of the following: a Desminpromoter, a chicken β-actin (CBA) promoter, or an endogenous human FXNpromoter (hFXNPro).
 5. The nucleic acid of claim 4, wherein the Desminpromoter comprises the sequence of SEQ ID NO:
 2. 6. The nucleic acid ofany one of claim 4, wherein the CBA promoter comprises the sequence ofSEQ ID NO:
 7. 7. The nucleic acid of any one of claims 4 to 6, whereinthe hFXNPro comprises the sequence of SEQ ID NO:
 8. 8. The nucleic acidof any one of claims 1 to 7, wherein the truncated human FXN 3′ UTR hasthe sequence of SEQ ID NO:
 3. 9. The nucleic acid of any one of claims 1to 8, wherein the expression construct comprises the sequence of SEQ IDNO:
 4. 10. The nucleic acid of any one of claims 1 to 9, wherein thenucleic acid is a recombinant adeno-associated virus (rAAV) vector. 11.The nucleic acid of claim 10, wherein the nucleic acid is asingle-stranded or self-complementary rAAV nucleic acid vector.
 12. Arecombinant adeno-associated virus (rAAV) particle comprising thenucleic acid of claim 10 or claim
 11. 13. The rAAV particle of claim 12,wherein the rAAV particle is an AAV9 particle.
 14. A compositioncomprising a plurality of the rAAV particle of claim 12 or claim
 13. 15.The composition of claim 14, further comprising a pharmaceuticallyacceptable carrier.
 16. A method of treating Friedreich's ataxia, themethod comprising: administering a therapeutically effective amount ofthe rAAV particle of claim 12 or claim 13 or the composition of claim 14or claim 15 to a subject having Friedreich's ataxia.
 17. The method ofclaim 16, wherein the rAAV particle or composition are administered viaintravenous injection.
 18. The method of claim 16, wherein the rAAVparticle or composition are administered via intrathecal injection. 19.The method of claim 16, wherein the rAAV particle or composition areadministered via intracisternal injection.
 20. The method of claim 17,further comprising administering the rAAV particle or composition viaintrathecal injection.
 21. The method of claim 17, further comprisingadministering the rAAV particle or composition via intracisternalinjection.
 22. The method of claim 20, wherein the ratio of rAAVparticle administered to the subject via intravenous injection to rAAVparticle administered to the subject via intrathecal injection is 1:10.23. The method of claim 21, wherein the ratio of rAAV particleadministered to the subject via intravenous injection to rAAV particleadministered to the subject via intracistemrnal injection is 1:10.